Abstract: In recent years, perovskite solar cells (PSCs) have become a research focus in the field of photovoltaics. The efficiency of PSCs has increased from 3.8% (in 2009) to 24.2% (in 2019) in only a few years, which can be compared with commercialized thin film solar cells based on Si; however, the instability of the PSCs hinders its wide application. The stability of PSCs mainly includes the stability of perovskites and other functional layer materials. This review focused on the factors limiting the stability of PSCs, such as humidity, oxygen, light, and heat. At the same time, recent strategies were summarized to overcome stability such as perovskite composition and structure optimization, interface modification, charge transport material improvement, and encapsulation.