Abstract: An excellent organolead halide perovskite film is important for the good performance of perovskite solar cells (PSCs). However, defects in perovskite crystals can affect the photovoltaic properties and stability of solar cells. To solve this problem, this study incorporated a complex of CdS and Cd(SCN₂H₄)₂Cl₂ into the CH₃NH₃PbI₃ active layer. The effects of different doping concentrations of CdS and Cd(SCN₂H₄)₂Cl₂ on the performance and stability of PSCs were analyzed. Results showed that doping appropriate incorporation concentrations of CdS and Cd(SCN₂H₄)₂Cl₂ in CH₃NH₃PbI₃ can improve the performance of the prepared solar cells. In specific, CdS and Cd(SCN₂H₄)₂Cl₂ can effectively passivate the defects in perovskite crystals, thereby suppressing the charge recombination in PSCs and promoting the charge extraction at the TiO₂/perovskite interface. Due to the reduction of perovskite crystal defects and the enhancement of compactness of the CdS:Cd(SCN₂H₄)₂Cl₂:CH₃NH₃PbI₃ composite film, the stability of PSCs is significantly improved.