New-type back reflectors based on one-dimensional photonic crystal (1D PC) for amorphous silicon thin film solar cells have been investigated, designed and fabricated. These 1D PCs consist of alternating amorphous Si (a-Si) and silicon dioxide (SiOx), of which the deposition process is compatible with current silicon thin film solar cells technology. Results indicate that the total reflectance of 1D PCs increases with the increase of period number. An average reflectance over 96% can be achieved in the range from 500 to 750 nm with 4 periods or more. Applying the 4-period 1D PC as back reflector in NIP amorphous silicon thin film solar cell with device-configuration of glass/1D PC/AZO/NIP a-Si:H/ITO, a conversion efficiency of 7.9% can be obtained, which is comparable to the AZO/Ag-based solar cell of 7.7% and is much better than the SS-based solar cell of 6.9% (a relative enhancement of 14.5%).