In order to solve the problem that the flow characteristics of the plunger type balanced control valve designed by relying on empirical equations deviate from the expected linear type,a scheme to optimize the linear plunger type control valve spool structure was proposed.The flow coefficient and the flow coefficient increment were taken as the criteria for evaluating the linearity fit,taking the experimental test as the premise and the numerical simulation as the main means,the spool structure was adjusted and optimized section by section,and the reasonableness and accuracy of the scheme through numerical simulation were verified.The results show that the optimized spool structure makes the flow characteristics fit linearly,and the deviation of the flow coefficient at each opening degree from the theoretical value of 8% or more before optimization is reduced to less than 2%;the deviation of the flow coefficient increment at each opening degree from the theoretical value of 15% or more before optimization,with the maximum value of 63.26%,is reduced to less than 5%,with the maximum value of only 13.62%.