Organometal halide perovskite as a promising absorber in solar cells has caught tremendous attention in the past few years. Herein, a hydrophobic PCBM layer was introduced into planar heterojunction perovskite solar cells to form the TiO₂/PCBM double blocking layer. The bilayer structure assures the formation of a dense, smooth, and pinhole-free blocking layer. And the PCBM layer can also be in favor of larger grain size perovskite film and further passivate the TiO₂ blocking layer. Scanning electron microscope, atomic force microscope, and X-ray diffraction (XRD) results suggest the formation of a uniform and compact CH₃NH₃PbI_3−xCl_x perovskite layer on the PCBM-modified TiO₂ blocking layer. The solar cell has reached a PCE up to 16.37%, which is greatly larger than the control device with a PCE of 10.81%.