A series of N-I-P amorphous silicon solar cells is prepared by RF-PECVD,whose P-layer is made of hydrogenated crystallized silicon (cryst-Si:H).The structure of the solar cells is Al/glass/SnO2/N(a-Si:H)/I(a-Si:H)/P(cryst-Si:H)/ITO/Al.Hydrogen plasma treatment is adopted to ensure the growth of cry-Si:H on amorphous substrate.The performance of solar cells is optimized by adjusting the thickness of P-layer and N-layer and the time of hydrogen plasma treatment.The results show that high-quality P-type cryst-Si:H can be obtained by hydrogen plasma treatment at the interface of a-Si:H I-layer.When the deposition time of N-layer and P-layer was optimized respectively,the a-Si:H solar cell with conversion efficiency of 6.40% is obtained.The performance of the solar cells can be improved by adjusting the structure of P-layer.