Two-dimensional high-frequency rotary valve is a kind of rotary valve designed by using spool with two degrees of freedom. When the spool rotates at a high speed, the velocity variation of fluid flowing through the valve ports generates periodic hydraulic torque on the spool, which imposes negative effects on the spool movement or even adversely affects the function of the valve. By calculating the flow fields in the chamber of 2D high-frequency rotary valve with different spool geometrical configurations, the influences of different geometrical dimensions on the average pressure and the average velocity around the notch walls and the flow moment imposed on the spool are presented. The results show that the structure and the layout of No.3 spool unit and No.4 are reasonable, and that the greater the spool groove bottom height h is, the more smoothly the hydraulic moment changes and the greater the flow rate through the valve port is.