The carrier transport layer plays a critical role in high efficiency and stable perovskite solar cells (PSCs). Herein, CsPbBr3 quantum dots-sensitized mesoporous TiO2 (CPB-TiO2) electron transport layer for fabricating high-quality perovskite films with enhanced phase stability is developed. The CPB-TiO2 layer enhances the perovskite crystallinity, phase stability, and reduces the nonradiative carrier recombination in PSCs. As a result, the CPB-TiO2 significantly improves the power conversion efficiency of FAPbI(3) PSCs from 23.11% to 24.46% and reduces the device hysteresis. The CPB-TiO2-FAPbI(3) device shows enhanced stability, retaining 90% of its initial efficiency after 500 h operation at maximum power point tracking under 1 sun illumination, whereas the control device degrades to 80% of initial performance in the first 200 h. In addition, this strategy is applicable to CsPbI3 perovskite, which provides a new and general strategy for preparing high-efficiency PSCs.