To analyze the relationship between the sealing assembly structure of aviation high-pressure directional valves and their internal fluid medium flow field, based on the working principle of this type of directional valve and the basic theory of fluid mechanics, the two-dimensional grid model of the directional valve with different assembly characteristics formed by different pressure pin structures and seals is established, and the corresponding boundary conditions are set. The flow field characteristics of valve chambers with different assembly structures were simulated using simulation analysis methods, and the corresponding distribution patterns of flow field pressure characteristics and vector characteristics were obtained. And calculate the pressure in area A of the valve core to obtain the pressure change curve. The results show that under a certain flow area, the flow field distribution of the valve cavity formed by different assembly structures is the same. The larger pressure and flow rate of state 1 and state 2 appear at the contact position between the pressure pin and the seal. The larger pressure and flow rate of state 3 appear in the process of medium entering the valve, and the vortex in the flow process has little effect on the structure of state 3, while the pressure distribution of the cone structure in region A is consistent with the flow field distribution, which is more uniform in state 3.