This review discusses the application of piezoelectric materials in wastewater treatment, focusing on piezo-photocatalysis. Industrialization, population growth, and human activities have led to severe water pollution, necessitating effective treatment methods. Piezoelectric materials, when combined with sunlight, offer a new approach for water purification. These materials, such as lead, barium, KNN, and bismuth perovskites, can achieve nearly 100% efficiency when piezoelectricity is combined with photocatalysis. The review covers various lead-free piezoelectric materials, their degradation efficiency, and possible mechanisms in piezo-photocatalysis. It also discusses the properties of piezoelectric materials, including their ability to convert mechanical energy into electrical energy. Piezoelectricity was first discovered by the Curie brothers in 1880. Piezoelectric materials generate an electric charge when subjected to mechanical stress, and this effect can be reversed. The piezoelectric effect is directly related to the intensity of the applied electric field. Piezoelectric materials must have an asymmetrical arrangement of positive and negative charges in their unit cell. Materials without inversion symmetry are non-centrosymmetric and can exhibit piezoelectricity. Barium titanate is an example of a ferroelectric material that exhibits spontaneous polarization. The review highlights the importance of understanding piezo-photocatalysis for lead-free piezoelectric materials in wastewater treatment. The study aims to provide researchers with a comprehensive understanding of lead-free piezoelectric materials and their potential applications in wastewater treatment.This review discusses the application of piezoelectric materials in wastewater treatment, focusing on piezo-photocatalysis. Industrialization, population growth, and human activities have led to severe water pollution, necessitating effective treatment methods. Piezoelectric materials, when combined with sunlight, offer a new approach for water purification. These materials, such as lead, barium, KNN, and bismuth perovskites, can achieve nearly 100% efficiency when piezoelectricity is combined with photocatalysis. The review covers various lead-free piezoelectric materials, their degradation efficiency, and possible mechanisms in piezo-photocatalysis. It also discusses the properties of piezoelectric materials, including their ability to convert mechanical energy into electrical energy. Piezoelectricity was first discovered by the Curie brothers in 1880. Piezoelectric materials generate an electric charge when subjected to mechanical stress, and this effect can be reversed. The piezoelectric effect is directly related to the intensity of the applied electric field. Piezoelectric materials must have an asymmetrical arrangement of positive and negative charges in their unit cell. Materials without inversion symmetry are non-centrosymmetric and can exhibit piezoelectricity. Barium titanate is an example of a ferroelectric material that exhibits spontaneous polarization. The review highlights the importance of understanding piezo-photocatalysis for lead-free piezoelectric materials in wastewater treatment. The study aims to provide researchers with a comprehensive understanding of lead-free piezoelectric materials and their potential applications in wastewater treatment.