Perovskite solar cells (PSCs) have attracted great attention due to their rapidly improved power conversion efficiency (PCE), which is up to 25.5%, comparable to commercial Si-based solar cells. Currently, stability is one of the key obstacles to their commercialization. Compared with organic–inorganic PSCs with volatile organic components, all-inorganic PSCs exhibit excellent thermal stability, and thus have attracted more and more attention in recent years. Among them, PSCs based on CsPbI₃ perovskite are the most eye-catching because of its ideal bandgap (1.73 eV) and excellent light absorption. Here, we systematically review strategies to improve the efficiency and stability of CsPbI₃ PSCs from their early days to recent advances. The improvement mechanisms are discussed from the aspects of film formation technology, additive engineering, dimensionality engineering, doping engineering and quantum dot technology. In the end, the future development direction and obstacles of CsPbI₃ PSCs are also discussed.