Aiming at the difficulty in design of throttling window profile for sleeve regulating valve,according to the related theories of fluid mechanic,flow characteristic and geometric equation of the window profile,the parametric design of its window profile with equal percentage flow characteristic was researched.Taking the DN80-Cv，max (44) sleeve regulating valve and DN200-Cv，max (275) sleeve regulating valve which turndown ratio are both 50∶1 as examples,the window profiles were designed based on the theoretical research.Simulated flow experiments were performed on the models of the two valves at 5%,10%,20%,… ,100% opening respectively by using ANSYS Fluent software.The results show that the errors between the simulation flow coefficient and the theoretical flow coefficient at each opening are not more than 10%,which meets the precision design requirements of the throttling window.Flow tests were carried out on the 5%,10%,20%,...,100% opening models of the two regulating valves.The results show that the error between test flow coefficient and theoretical flow coefficient is large when the valve is opened at 5% and 10%;when the valve is opened at various openings from 20% to 100%,the error between test flow coefficient and theoretical flow coefficient is all within 10%,and the flow control accuracy is high;the circumferential clearance between throttle sleeve and valve plug has a great influence on flow coefficient when the valve is in small opening;the flow characteristic curves of theory,simulation and experiment are highly consistent,the correctness of the proposed method is verified.