Aiming at the design difficulties of the throttle sleeve of the sleeve regulating valve, the parameterization of the throttle sleeve with equal percentage flow characteristics was researched according to the flow equation of the regulating valve and the relevant theories of flow characteristics,and combined with the geometric design equation of the orifice. Taking the DN50(Cvmax24), DN250(Cvmax450) and DN500(Cvmax1860) sleeve regulating valves with turndown ratio of 50∶1 as examples, the porous throttle sleeves were designed. The simulation experiments were performed to 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% opening models of the three regulating valve by using Fluent simulation software. The results show that the relative error of simulation and theoretical flow coefficient is within 10% except for the 10% opening model for DN50(Cvmax24) sleeve regulating valve; the relative errors of simulation and theoretical flow coefficients of DN250(Cvmax450) and DN500(Cvmax1860) sleeve regulating valves at all openings are within 10%, and the relative accuracy is high; the flow characteristics curves of theoretical and experimental are in good agreement. The research results supplement the deficiency in the design method of the throttle sleeve of the sleeve regulating valve, and provide assistance for the development of the regulating valve industry.