Highly transparent and crystallized nickel oxide thin film through magnetron sputtering is incorporated in CH3NH3PbI3 planar heterojunction perovskite solar cells (PSCs). In this work, the influence of substrate temperature on NiO film during magnetron sputtering and corresponding performance of PSCs were investigated. NiO thin films were prepared with different substrate temperatures, i.e., 20 °C, 150 °C, and 300 °C, named as 20-NiO, 150-NiO, and 300-NiO, separately. It is found that higher substrate temperature leads to better crystallinity of NiO film, and corresponding a higher PSCs efficiency. PSCs based on 300-NiO thin films’ inorganic hole transport layer show the best efficiency (up to 14.11%), which is about 32% higher than that of device based on 20-NiO. This is mainly due to the fact of 300-NiO thin films with the better light transmittance and higher hole mobility, promoting light absorption and photo-generated charge separation efficiency of perovskite layer, which leads to an improvement in device performance.