Abstract: The steam turbine control valve, as the core component of the flow control for the thermal power plant,directly affects the economy and safety of the unit. The low pressure air is often used in the control valve’s modeling experiment of flow and vibration characteristics instead of high temperature steam. However, whether the test can reproduce the flow characteristics of prototype parameters under the condition of model parameters remains to be verified. In this paper, the flow characteristics in the valve under prototype parameters and modeling parameters were analyzed based on the experiments and numerical simulations. The results show that the modeling experiment can report the flow characteristics,pressure loss and flow patterns in control valve of prototype parameters based on geometrical similarity, the same pressure ratio and Reynolds number of entering self-modeling area.However, to simulate the dynamic characteristics of flow and the response characteristics of the valve stem system for the modeling experiment, the Reynolds number of the modeling experiment should be the same with the prototype parameters.