Perovskite solar cells (PSCs) have been developed as a new photovoltaic technology due to their excellent photoelectric conversion efficiency and low cost of manufacturing. The research of PSCs has been boosted especially in the past ten years, and the performance of PSCs has been greatly improved. However, there are more efforts to be done in this field to push the PSCs into the photovoltaic market. The main problem is caused by the limitations of the perovskite film itself during the manufacturing, where the inevitable existence of defects would seriously affect the number and mobility of carriers in the PSCs. All these defects can restrict the improvement of the efficiency and stability of PSCs. In this review article, we briefly introduce the classification of perovskite and their defects. Different strategies for passivation of perovskite films developed in recent years were summarized accordingly. It is expected that the current study would benefit the researchers in the field of perovskite materials and provide valuable insights for them to choose suitable passivating agents.