In order to solve low feed control efficiency, easy leakage and other problems of inlet valve in the steam explosion systems, a feed valve which simultaneously achieves feeding, sealing and opening was designed. Through theoretical analysis of valve core according to material and working environment of valve and intensity using ANSYS Workbench, the maximum deformation position of valve core, the optimum diameter and the best speed of screw shaft which can ensure the stability of feed and seal were obtained. Through theoretical calculation and intensity check, the strength of valve core fully meets the design requirements under normal working conditions. The experimental test for the impact of feeding time and speed on the stability of feed shows that the optimal speed for feed is 200 r/min and the best feeding time is 5 min, to feed 150 kg corn stalks.