Condensate regulating valve is a key equipment to maintain the water level of deaerator and regulate the pressure of mother tube, which plays an important role in nuclear power operation. A nuclear power condensate double valve group as the research object, through the three-dimensional flow field of non-constant simulation, the double valve synchronous adjustment under the opening on the internal flow field changes, energy dissipation process and noise characteristics of the condensate valve group, and the flow field simulation results as the applied load, the use of finite element simulation method for structural strength analysis and modal vibration study of the valve body. The results show that: the multi-stage sleeve orifice structure is the main throttling and pressure reducing element in the valve, and there is a large velocity and pressure gradient inside; as the valve opening increases, the maximum velocity, turbulence and noise position inside the valve are gradually clustered upward from the bottom of the sleeve, and the value gradually decreases; the excitation load along the main flow direction inside the valve causes the largest local deformation of the sleeve, and the long-term operation may be the main cause of sleeve fatigue fracture cause.