Pn tandem design of sensitized solar cell is a novel concept holding the potential to overcome the efficiency limitation of conventional single junction sensitized solar cells. To significantly improve photocurrent density (Jsc) of p-type half-cell is prerequisite for the realization of highly efficient pn tandem cell in the future. This paper has demonstrated effective photocathodes based on novel organometal halide perovskites sensitized mesoporous NiO in liquid electrolyte based p-type solar cells. Acceptably high Jsc up to 9.47 mA cm-2 and efficiency up to 0.71% have been achieved based on the CH3NH3PbI3/NiO solar cell at 100 mW cm-2 light intensity, which are significantly higher than any of previously reported liquid electrolyte based p-type solar cells based on sensitizers of organic dyes or inorganic quantum dots. The dense blocking layer made by spray pyrolysis of nickel acetylacetonate holds the key on determining the current flow direction of the solar cells. High hole injection efficiency at the perovskites/NiO interface and the high hole collection efficiency through the mesoporous NiO network have been proved by the time-resolved photoluminescence and transient photocurrent/photovoltage decay measurements. The limitation of these p-type solar cells primarily rests with the adverse light absorption by the NiO mesoporous film; the secondary limitation arises from the highly viscous ethyl acetate based electrolyte, which is helpful for the solar cell stability but hinders fluent diffusion into the pore channels, giving rise to nonlinear dependence of Jsc on light intensity.