A kind of photolithography technology of positive photosensitive polyimide was introduced in the process of CdS ultraviolet device fabrication. Photosensitive polyimide can be the surface passivation of CdS ultraviolet device after imidization,and the relevant experiments were carried out. The experimental results show that this technology can meet the requirements of CdS ultraviolet device and improve the production efficiency and the yield of CdS ultraviolet device.