Blue-green infrastructure (BGI) integrates semi-natural and engineered elements to provide benefits like stormwater management, water purification, heat mitigation, and habitat provision. However, current BGI designs prioritize engineering goals, neglecting its ecological potential. This study advocates integrating ecological and engineering objectives in BGI design to enhance performance and biodiversity. Through a literature review, it emphasizes the importance of species diversity, abundance, and ecological processes to improve engineering performance, resilience, and reduce maintenance costs. Interdisciplinary collaboration is crucial to balance engineering and ecological goals. BGI, including vegetated basins, green roofs, and stormwater ponds, helps restore natural cycles in cities. While traditionally focused on stormwater management, BGI now includes functions like heat mitigation and biodiversity conservation. However, ecological aspects are often overlooked by engineers. Biodiversity provides ecosystem services and enhances BGI performance. For example, increasing plant species in BGI can improve water absorption and quality. Ecological engineering, which applies ecological theories to engineering, has applications in flood protection and landslide prevention. In BGI, it helps understand how biodiversity contributes to engineering objectives like stormwater management and water purification. However, many ecological theories remain underexplored. BGI can mitigate the biodiversity crisis in cities, which face threats like land-use change and climate change. Urban areas can provide valuable habitats, and BGI can enhance biodiversity by supporting species' needs. However, trade-offs may arise when BGI design cannot accommodate both ecological and engineering goals. This study calls for a holistic approach to BGI design, considering the bidirectional relationship between BGI and biodiversity. It highlights how biodiversity affects BGI performance and how BGI impacts biodiversity. The study synthesizes literature on the benefits of ecological engineering in BGI, emphasizing the importance of biodiversity for stormwater management, water quality, and heat mitigation. Biodiversity enhances BGI performance through species diversity, abundance, and ecological processes. For example, diverse plant assemblages improve stormwater retention and heat mitigation. Functional diversity of species traits is more important than species richness. Increasing plant abundance improves evapotranspiration and heat mitigation. Ecological processes like species interactions and natural succession should be harnessed rather than controlled. Studies show that interactions between vegetation and soil biodiversity improve water quality and nutrient processing. Allowing natural succession increases species diversity and functional diversity. Biodiversity enhances BGI resilience to droughts, heavy rainfall, pests, and seasonal variations. High species diversity increases functional redundancy and response diversity, improving resilience. However, studies on biodiversity and infrastructure resilience are limited. Maintaining biodiversity can reduce maintenance costs by minimizing the need for frequent interventions. However, reduced maintenance may facilitate invasive species spread. Balancing maintenance practices is essential to ensure both engineering objectives and biodiversity. Engineering for biodiversity involves designing BGI to conserve and restore biodiversity. This includes maximizing surface area, increasing vegetation diversity, ensuring soil and water quality, and providing structural heterogeneity. Urban planning and design affect biodiversity atBlue-green infrastructure (BGI) integrates semi-natural and engineered elements to provide benefits like stormwater management, water purification, heat mitigation, and habitat provision. However, current BGI designs prioritize engineering goals, neglecting its ecological potential. This study advocates integrating ecological and engineering objectives in BGI design to enhance performance and biodiversity. Through a literature review, it emphasizes the importance of species diversity, abundance, and ecological processes to improve engineering performance, resilience, and reduce maintenance costs. Interdisciplinary collaboration is crucial to balance engineering and ecological goals. BGI, including vegetated basins, green roofs, and stormwater ponds, helps restore natural cycles in cities. While traditionally focused on stormwater management, BGI now includes functions like heat mitigation and biodiversity conservation. However, ecological aspects are often overlooked by engineers. Biodiversity provides ecosystem services and enhances BGI performance. For example, increasing plant species in BGI can improve water absorption and quality. Ecological engineering, which applies ecological theories to engineering, has applications in flood protection and landslide prevention. In BGI, it helps understand how biodiversity contributes to engineering objectives like stormwater management and water purification. However, many ecological theories remain underexplored. BGI can mitigate the biodiversity crisis in cities, which face threats like land-use change and climate change. Urban areas can provide valuable habitats, and BGI can enhance biodiversity by supporting species' needs. However, trade-offs may arise when BGI design cannot accommodate both ecological and engineering goals. This study calls for a holistic approach to BGI design, considering the bidirectional relationship between BGI and biodiversity. It highlights how biodiversity affects BGI performance and how BGI impacts biodiversity. The study synthesizes literature on the benefits of ecological engineering in BGI, emphasizing the importance of biodiversity for stormwater management, water quality, and heat mitigation. Biodiversity enhances BGI performance through species diversity, abundance, and ecological processes. For example, diverse plant assemblages improve stormwater retention and heat mitigation. Functional diversity of species traits is more important than species richness. Increasing plant abundance improves evapotranspiration and heat mitigation. Ecological processes like species interactions and natural succession should be harnessed rather than controlled. Studies show that interactions between vegetation and soil biodiversity improve water quality and nutrient processing. Allowing natural succession increases species diversity and functional diversity. Biodiversity enhances BGI resilience to droughts, heavy rainfall, pests, and seasonal variations. High species diversity increases functional redundancy and response diversity, improving resilience. However, studies on biodiversity and infrastructure resilience are limited. Maintaining biodiversity can reduce maintenance costs by minimizing the need for frequent interventions. However, reduced maintenance may facilitate invasive species spread. Balancing maintenance practices is essential to ensure both engineering objectives and biodiversity. Engineering for biodiversity involves designing BGI to conserve and restore biodiversity. This includes maximizing surface area, increasing vegetation diversity, ensuring soil and water quality, and providing structural heterogeneity. Urban planning and design affect biodiversity at