CeO x has been widely used in optoelectronic devices due to its special electronic and optical structure. Herein, CeO x was directly doped into ZnO to successfully construct a ZnO/CeO x electron transport material (ETM) used in perovskite solar cells (PSCs). The incorporation of CeO x can regulate the chemical compatibility between ZnO and perovskite, unmatched energy levels, and poor UV stability, further enhancing the cell performance and stability of PSCs. As expected, the best efficiency of fabricated CH3NH3PbI3-PSCs based on ZnO/CeO x as the ETM was up to 19.5%. In contrast, the efficiency of PSCs with pure ZnO was 16.0%. Moreover, compared with PSCs based on ZnO, ZnO/CeO x-based PSCs exhibited significantly enhanced moisture, and thermal and UV stability. These results point to the introduction of rare-earth oxides, which could accelerate the industrialization of PSCs.