Aiming at the surge problem of magnetic suspension fluid machinery, according to the fluctuation of mass flow and pressure rise in the surge State of fluid machinery system, a surge control strategy based on mass flow is adopted. The surge controller obtains the axial adjustment clearance value of the impeller and inputs it into the closed-loop control system of the axial magnetic bearing as the suspension position reference signal, so as to change the axial position of the magnetic levitation fluid machinery rotor under the action of the axial magnetic bearing system, that is, change the blade tip clearance of the impeller, so as to realize the active control of surge. The simulation results show that when surge control is applied, the stable operation range of fluid machinery can be extended from 15.5% throttle opening under uncontrolled to 14% under surge control. The surge frequency is identified by simulating the excitation, and the influence of the control parameters in the PID controller on the surge control performance is studied. This method has the advantages of simple control, no additional hardware and no efficiency loss.