A precursor blending solution method is used to prepare CH3NH3PbI3:CdS layer. The CH3NH3PbI3:CdS bulk heterojunction perovskite solar cells are fabricated. The efficiency of the cell is improved due to the introduction of CdS. The highest efficiency of prepared CH3NH3PbI3:CdS solar cells is (16.5 ± 0.2)%.