The study prepared thin film solar cells using hydrogenated microcrystalline silicon (c-Si:H) by hot-wire chemical vapor deposition (HWCVD). Hydrogen dilution profiling was used to deposit the boron-doped p-layer on the SnO2:F substrate. The c-Si:H solar cell with triple hydrogen dilution grades in the p-layer has a high photoconversion efficiency of 4.5 as a result of the improvement in the electrical and the antireflection properties of the cell. The short circuit current (Jsc) and the open circuit voltage (Voc) of the solar cell are 19.7 mA/cm2 and 450 mV, respectively. The graded hydrogen concentration in the p-layer improves the crystallinity and the antireflection of the absorbing layer (intrinsic layer), thereby enhancing the Jsc. The high Voc is ascribed to that a high hydrogen dilution ratio may enhance boron doping in the p-layer leading to the improvement of the Voc.