Abstract: In order to investigate the influence of chamfering depth and angle of the regulating sleeve throttling hole on the internal flow field and structural reliability of a high-pressure bypass valve, numerical calculations and one-way thermos-fluid-solid coupling analysis of the internal flow field of the valve were conducted. The results show that after throttling, steam will form shock waves and a series of shock wave trains that disappear at the bottom cover of the secondary throttling sleeve. In addition, the large pressure difference on both sides of the sealing surface of the annular regulating sleeve is the main cause of the sealing surface deformation. Secondly, aiming to reduce the deformation of the regulating sleeve sealing surface, the influence of the chamfering angle and depth of the throttling hole on the flow field and sealing surface deformation was investigated. The results show that chamfering can significantly reduce the pressure difference and deformation of the sealing surface on both sides of the regulating sleeve. When the chamfering angle is 72.5°, the reduction of shape variable on both sides of the regulating sleeve is 17.06% and 15.72%, respectively. This research results provide a basis for optimizing valve flow characteristics and reducing valve deformation.