Abstract: To understand the changes in kinetic characteristics of distribution pressure-reducing valves, field tests are conducted to acquire data related to random vibration of the valves. Through analysis on vibration mechanism of pressurereducing valves, the finite-element analysis software, Workbench, is used to establish the finite-element model for RMG530 pressure-reducing valves, which can be used to determine natural frequency of the pressure-reducing valve structures. In addition, with consideration to operation parameters of an offtake station and changes of Young′s modulus of valve materials with temperatures, impacts of thermal-fluid-solid coupling to calculation results are identified. Ultimately, on the basis of modal analysis of pressure-reducing valves, the modal superposition method is deployed to calculate dynamic responses of pressure-reducing valve structures and to analyze features of such dynamic responses in both time domain and frequency domain. Relevant research results show that design for structure of pressure-reducing valve is quite conservative. During gas offtake, stresses and displacement responses have low amplitudes, which are not sufficient to induce resonance.