In recent years, the emerging organic and inorganic hybrid perovskite solar cells have made rapid progress. In just ten years, its photoelectric conversion efficiency has rapidly developed from 3.8% to the current certified efficiency of 25.2%, which is regarded as one of the most potential solar cells. Although perovskite solar cells have high photoelectric conversion efficiency comparable to polysilicon thin film cells, the long-term stability of the cells remains a major challenge hindering their commercialization. There are many defects on the surface and grain boundary of perovskite. Interface passivation is an important and effective strategy to improve the stability of perovskite solar cells. Two-dimensional perovskite materials are organic amine and inorganic layer alternate layered perovskite, with bulky organic ammonium cations. Compared with the traditional three-dimensional perovskite materials, the stability for the environment is good, with the flexible and adjustable structure. The 3D perovskite’s surface is modified by a two-dimensional perovskite to passivate defects, ensuring the stability and at the same time improving the efficiency of perovskite solar cells. In addition, suitable passivation agent molecules can also passivate defects effectively. This paper reviews the unstable factors of perovskite solar cells, summarizes the research progress in interface passivation of perovskite solar cell, points out the great potential of two-dimensional perovskite materials’ development and the principle of finding suitable passivation agent molecules, which is expected to provide useful guidance for obtaining high-performance perovskite solar cells and realizing commercialization.