According to microelectronic flat processes,Cadmium Sulfide(CdS)Schottky ultraviolet photodetector was fabricated after evaporating Pt by electron beam to form Schottky contact.The I-V characteristic,spectrum responsivity and quantum efficiency were measured and analyzed.The results show that the response wavelength range is from 250 nm to 500 nm at room temperature without any biased voltage,and maximal spectrum responsivity is 0.285 A/W at 500 nm,and the quantum efficiency is 75.3%.The Schottky barrier height and ideality factor are 0.859 eV and 1.024 respectively which is calculated by thermionic emission theory.