A linear throttling groove was presented, by which the area of flow section was directly proportional to the size of the entrance. When the linear throttling groove was used on the electromagnetic proportion throttle valve, it was realized that the relation between the flow through valve port and the displacement of valve core was regular linear change; with proportional electromagnet, it could achieve proportional control between the valve port flow and the electrical signal easily. Simulating the steady state characteristics of the electromagnetic proportion throttle valve with MATLAB based on its practical working environment, the flow characteristic curves at different valve port sizes, the stiffness characteristic curves and the relation curves between valve port sizes and the flow were gotten. Then the simulation results were analyzed. The analysis results have an important guiding significance for the design parameters optimization of the electromagnetic proportion throttle valve.