Abstract: This paper makes a study and analysis on the transmission spectrum of ZnO thin film when the cadmium concentration is 2%-10% by using the slide and quartz as the substrate.In the experiment,only relatively strong UV emission peaks arefound and there is no deep-level emission,which indicates that the emission in the UV range is the predominant emission of ZnO: Cd thin film and so is the band-to-band transition.The controlled doping method is adopted to prepare ZnO: Cd thin film,and heat treatment is employed to improve the performance of the film and optimize the process parameters.