This paper reviews the development of perovskite solar cells at first. Then, we summarize some important factors that affect the stability of perovskite solar cells, including water vapor, oxygen, lights, high temperature conditions, electron transport layer (ETL), hole transport layer (HTL) and preparation methods. Meanwhile, we focus on the understanding of the instability mechanism and find some ways to improve the stability of cells. In the end, based on the current research, we forecast the development of perovskite solar cells. © 2020, Science Press. All right reserved.