Based on the excellent optoelectronic properties of organic-inorganic hybrids perovskite materials, the power conversion efficiency of perovskite solar cells (PSCs) is rapidly increasing. However, factors that restrict the performance of PSCs still exist, such as interface and stability problems. Problems, such as band mismatching, carrier recombination and chemical reaction between interfaces, could be alleviated by introducing a buffer layer (BL) with a proper band structure between different layers. Moreover, stability as well as charge separation and collection could also be efficiently improved in PSCs. In this paper, an overview of the most contemporary strategies of BLs was provided. The passivation mechanism of BLs at different interfaces are highlighted and discussed in detail. Furthermore, the performances of recently developed BLs in PSCs are compared. Finally, we elaborate on the remaining challenges and future directions for the development of BLs to achieve high-efficiency and high-stability PSCs.