Abstract: The flow characteristics of nuclear power control valves are one of the most concerned issues in nuclear power plant applications. Two CFD numerical tools Simerics MP+ and Fluent were utilized to study the flow characteristics of nuclear power main feed-water control valves. Related simulation experiments were carried out and the results indicate that when the relative opening of the nuclear power main feed-water valve is less than 70%, the valve has an equal percentage flow characteristic. When the relative opening is greater than 70%, the valve's characteristic is close to a linear flow . Compared with related real experimental results, the relative error of the calculation result of Simerics MP+ is less than that of Fluent. This means that valve Simerics MP+ simulation is closer to the real value of the flow characteristic. The calculation results of the pressure field distribution contours are basically consistent with each other, and the velocity field distribution contours are slightly different from each other, which is reflected in the inconsistent flow velocity distribution in the downstream area of the valve. The advantage of Simerics MP+ in valve dynamics research is that it is easy to realize and can provide a reference for nuclear power regulating valve dynamic research.