The purpose of this study is to investigate the application of polyurethane screen deck in linear vibrating screen. The dynamic model of polyurethane screen deck in sieving is built. The maximum deformation of grizzly bar is studied and the section size of grizzly bar is optimized. The maximum deformation of grizzly bar is mainly affected by the vibration amplitude and the inclined angle of the vibrating screen. The optimization curve between the height and width of grizzly bar is obtained.