In order to systematically study the influence of valve body structural parameters on the flow resistance characteristics of the regulating valve, the model of the regulating valve body in power station was established by using the numerical simulation method. Combined with the orthogonal experimental design, the influence of different structural parameters of the regulating valve body on the convection resistance characteristics was studied. The results show that the influence degree of the structural parameters of the regulating valve body on the convection resistance coefficient is in the order of upper chamber radius > lower chamber height > upper chamber height > valve body half-length > lower chamber radius > middle chamber radius. Meanwhile, the optimization analysis of the inlet angle of the valve body shows that the smaller the inlet angle is, the smaller the flow resistance coefficient is. The optimal structure obtained after orthogonal experiment optimization and inlet angle optimization, its flow resistance coefficient is reduced by 19.45% compared with the original structure, and the flow characteristic curve is more ideal. The research results can provide theoretical support for the structure optimization of sleeve type regulator valve.