In order to study the gas liquid two phase flow pattern ofthe new mixture pump ball valve, the three dimensional flow field of the ball valve model was established. Simulating the gasliquid twophase flow inside the valve by using CFD software was carried out. At open height of the ball valve was 0005 meter, the gas rate of 20%, 40%, 60%, 80% four kinds of working condition, simulation result was respectively analyzed, velocity field, pressure field and phase distribution of gas liquid two phase under different gas rate were obtained, and the influence law of gas rate to gas liquid two phase flow was discussed within the ball valve. Results show that in the valve clearance and velocity are larger, and in the pressure gradient is large, the lower seat chamfer is easy of cavitation. Gas rate has little influence of flow velocity, but affects the flow pattern. Gas is mainly distributed near the valve wall, away from the valve wallgas is less. When the gas content increased gradually, gas liquid two phase at phase interface is fluctuated largely. Research results reveal the law of gas liquid two phase flow in the valve, to provide certain reference for study of compressed mixture pumps gas liquid phase interface evolution and the mechanism of instability of a oneway valve.