In order to study the distribution of vibration and noise of transformer core, the sound field distribution of core vibration of a 200 kVA oil immersed transformer is analyzed based on the multi physical field coupling calculation of COMSOL. Firstly, the electromagnetic force multi physical field model of core vibration of 200 kVA oil immersed transformer is constructed by using COMSOL finite element calculation software. The magnetic field distribution of transformer core, the variation law of stress distribution and displacement distribution of core are calculated. The stress time domain data of typical positions of core are analyzed by spectrum, and the stress concentration of core is 100, 200 and 300 Hz. Then, the frequency domain data of the iron core surface acceleration calculated by the above multiple physical fields after FFT transformation is used as the excitation source of the sound field, the harmonic response of the sound field is analyzed, and the sound field distribution of the transformer iron core vibration is calculated. Finally, the correctness of the simulation data is verified by the no-load experimental data of a 200 kVA transformer. After comparison, it is found that it has a good agreement effect. The consistent law between simulation and experiment is that the vibration and noise frequency of transformer core is concentrated below 500 Hz, and it is found that the side sound pressure of transformer oil tank > upper sound pressure > front sound pressure; The sound pressure frequency content on the side and above the transformer oil tank is 100 Hz > 200 Hz>300 Hz, while the sound pressure frequency content on the front of the oil tank is 100 Hz>300 Hz>200 Hz.