The water seal of rock drill bears the combined action of rotation and impact in the working process,which is easy to cause Y-ring seal failure and fatigue failure.In order to improve the performance of rock drill water seal,by considering the rotation and impact motion,the sealing performance of Y-ring under different structural parameters studied by finite element simulation.Based on the orthogonal test method,taking the maximum contact stress and the maximum von Mises stress as the evaluation indexes of sealing performance,the main and secondary factors affecting the sealing performance were obtained through range analysis,and the structural parameters of Y-ring were optimized and improved.The results show that the factors significantly influencing the maximum contact stress are sealing lip thickness,chamfer length and sealing lip length.The maximum contact stress increases with the increase of sealing lip thickness and chamfer length,and decreases with the increase of sealing lip length.The factors significantly influencing the maximum von Mises stress are sealing lip thickness and depth,and the angle between lip and drill tail.The maximum von Mises stress increases with the increase of sealing lip depth and the angle between lip and drill tail,and decreases with the increase of sealing lip thickness.After optimization and improvement,the maximum contact stress and von Mises stress of Y-ring are reduced by 15% and 45% respectively.On the condition of ensuring the sealing effect,the decrease of the maximum contact stress reduces the wear of the Y-ring,while the significant decrease of the maximum von Mises stress greatly improves the service life of the Y-ring.