This review discusses the depolymerization and re/upcycling of biodegradable PLA plastics. With the increasing use of plastic products, environmental pollution and recycling challenges have become significant concerns. Biodegradable plastics, such as PLA, offer a sustainable alternative due to their ability to biodegrade. PLA is the most widely used biodegradable plastic, with a large market share, and is applied in various products like thin films, medical materials, and biodegradable straws. However, the widespread adoption of PLA is hindered by high costs, low recycling rates, and its complete degradation into water and carbon dioxide in natural conditions. Therefore, exploring solutions for the depolymerization and re/upcycling of PLA waste is crucial. The review outlines current PLA recycling methods, emphasizing the advantages of chemical re/upcycling. It explores recent breakthroughs and technical challenges in various chemical depolymerization methods. The review highlights the challenges and future possibilities in PLA plastics, emphasizing the pursuit of closed-loop recycling and upcycling. PLA is produced through polycondensation and ring-opening polymerization (ROP). The synthesis of PLA involves the dehydration of lactic acid, which can be reversed, leading to a decrease in molecular weight. Currently, PLA with high molecular weight is mainly produced through the ROP of lactide. However, the process is complex and requires purification of intermediates. PLA has several challenges, including high production costs and limited degradation in natural environments. Despite being biodegradable, PLA does not fully degrade in natural conditions, requiring specific environments like industrial composting. The chemical re/upcycling of PLA not only demonstrates technical feasibility but also holds significant scientific and practical value. Recent studies have demonstrated the conversion of waste PLA into valuable chemicals using catalysts such as Ru/TiO2, α-MoC, and ionic liquids. The review provides a comprehensive survey of advancements in the catalytic depolymerization of PLA polyesters and outlines the challenges in achieving effective closed-loop recycling and upcycling processes. The review discusses various depolymerization methods, including pyrolysis, hydrolysis, alcoholysis, enzymatic hydrolysis, and other methods. Each method has its advantages and challenges, with chemical re/upcycling being a promising solution for the sustainable management of PLA waste. The review emphasizes the importance of selecting appropriate solvents, nucleophilic reagents, and catalysts for efficient depolymerization and recycling of PLA. The strategic use of nucleophilic reagents, such as oxygen, nitrogen, carbon, and sulfur-based reagents, is crucial for the depolymerization process. The review concludes that chemical re/upcycling of PLA is a viable solution for sustainable plastic waste management.This review discusses the depolymerization and re/upcycling of biodegradable PLA plastics. With the increasing use of plastic products, environmental pollution and recycling challenges have become significant concerns. Biodegradable plastics, such as PLA, offer a sustainable alternative due to their ability to biodegrade. PLA is the most widely used biodegradable plastic, with a large market share, and is applied in various products like thin films, medical materials, and biodegradable straws. However, the widespread adoption of PLA is hindered by high costs, low recycling rates, and its complete degradation into water and carbon dioxide in natural conditions. Therefore, exploring solutions for the depolymerization and re/upcycling of PLA waste is crucial. The review outlines current PLA recycling methods, emphasizing the advantages of chemical re/upcycling. It explores recent breakthroughs and technical challenges in various chemical depolymerization methods. The review highlights the challenges and future possibilities in PLA plastics, emphasizing the pursuit of closed-loop recycling and upcycling. PLA is produced through polycondensation and ring-opening polymerization (ROP). The synthesis of PLA involves the dehydration of lactic acid, which can be reversed, leading to a decrease in molecular weight. Currently, PLA with high molecular weight is mainly produced through the ROP of lactide. However, the process is complex and requires purification of intermediates. PLA has several challenges, including high production costs and limited degradation in natural environments. Despite being biodegradable, PLA does not fully degrade in natural conditions, requiring specific environments like industrial composting. The chemical re/upcycling of PLA not only demonstrates technical feasibility but also holds significant scientific and practical value. Recent studies have demonstrated the conversion of waste PLA into valuable chemicals using catalysts such as Ru/TiO2, α-MoC, and ionic liquids. The review provides a comprehensive survey of advancements in the catalytic depolymerization of PLA polyesters and outlines the challenges in achieving effective closed-loop recycling and upcycling processes. The review discusses various depolymerization methods, including pyrolysis, hydrolysis, alcoholysis, enzymatic hydrolysis, and other methods. Each method has its advantages and challenges, with chemical re/upcycling being a promising solution for the sustainable management of PLA waste. The review emphasizes the importance of selecting appropriate solvents, nucleophilic reagents, and catalysts for efficient depolymerization and recycling of PLA. The strategic use of nucleophilic reagents, such as oxygen, nitrogen, carbon, and sulfur-based reagents, is crucial for the depolymerization process. The review concludes that chemical re/upcycling of PLA is a viable solution for sustainable plastic waste management.