Thin perovskite layers are crucial for fabricating semitransparent perovskite solar cells and tandem devices. However, this will reduce the light absorption of the device, resulting in low efficiency. To overcome this dilemma, we use textured fluorine doped SnO2 (FTO) substrates to trap light and enhance light absorption in thin perovskite solar cells. Both optical simulation and experimental demonstration show the successful application of this new strategy in enhancing the efficiency. In the meantime, the transmittance of the full cell beyond the perovskite absorption range is not sacrificed, which is pivotal for fabricating semitransparent perovskite solar cells and tandem devices.