The Ultra-High Voltage (UHV) shunt reactor generates a substantial number of acoustic signals during operation, which contains a wealth of crucial information. To accurately evaluate various acoustic indexes of the UHV shunt reactor, it is necessary to establish an accurate sound field model. This paper proposes a method for restoring the sound field of a UHV reactor based on equivalent transfer impedance. Based on the vibration data of the reactor tank surface, combined with the boundary element method and considering the influence of the firewall on the radiated sound field. The boundary condition of equivalent transfer impedance is used to simplify the firewall. Finally, the near sound field of the shunt reactor is accurately reconstructed and simulated. The results demonstrate that the sound field restoration simulation model exhibits high accuracy and reliability, significantly reducing the calculation steps and time of the model. Moreover, it also enhances calculation efficiency and provides a reliable method for comprehensively evaluating and optimizing the acoustic performance of UHV shunt reactors.