摘要： As a rising star of lead-free perovskite solar cells (PCSs), tin-based PSCs have drawn much attention and made promising progress during the past few years. Notably, interfaces in the tin-based PSCs device have great impacts on performance enhancements. In this Review, the authors first demonstrate why the interface is especially crucial for tin-based PSCs device. It is proposed that the engineering of i) interface between perovskite grains in the film and ii) interface within the PSCs device are of great significance on the improvement of device functionality and stability. Then, the up-to-date studies on interface engineering of tin-based PSCs are reviewed, including the following strategies: i) passivation of trap states; ii) modification of interfacial layers; iii) construction of 2D/3D structure. At last, a future perspective and remaining challenges in this field are given, aiming to provide a comprehensive understanding of interfaces in tin-based PSCs and give some new thoughts on interface engineering for efficient PSCs device.