The control properties of vortex valve for mass flow rate are numerically simulated. The time-dependent method is used to solve full Navier-Storkes governing equations. The calculation is made with the control mass added or not. The steady nozzle flowfield with vortex chamber is obtained and the nozzle mass flow rate is related with control mass flow rate. The results indicate that the vortex valve has good property for controlling nozzle mass flow rate.