Aiming at reducing the influences of the proportion accuracy of proportional controller on the energy efficiency of the three-component propellant,a tri-rotors proportion controller was proposed based on the working principle of tri-rotors flowmeters,and the proportional control performances of an engineering prototype machine were experimentally studied under the constant and variable flow conditions.The results indicate that the tri-rotors proportional controller has advantages of simple structure,easy processing,running smooth and low damping; in the case of constant flow condition,the proportion of the proportional controller is stable and has high accuracy,and it has no significant differences among different flow conditions; in the case of variable flow condition,the proportion of the proportional controller has slight fluctuations,and the fluctuation amplitudes decreases with the increase of the flow; the pressure loss caused by the fuel of the proportional controller is the largest,while it caused by the coolant of the proportional controller is the smallest.The research results provide a new method to develop higher accuracy proportional controllers,which are expecte.