Abstract: The seal ring structure was reformed to improve the sealing performance and the experiment about the rubber properties were carried out in the US AXEL laboratory. The rubber seal ring model was built and analyzed by ANSYS, and the strain and stress under working state were calculated with the maximum contact stress as working ability criteria. The effect of structure parameters on sealing performance was then analyzed and the geometry dimensions were optimized. It was shown that the suitable width of sealing surface is 1.5 mm and the compressing distance is 3 mm, which can prevent the problems of tightness and early failure of the diaphragm chamber. This work may offer some useful information for the design of seal ring.