During practical operation, harmonic injection can cause the reactor to produce vibration noise with complex harmonic content, which can lead to a significant increase in the overall sound pressure level and noise-related problems. Therefore, it is necessary to study the electromagnetic vibration and noise of series reactors under harmonics. In the article, a finite element model of the reactor is established and an excitation loading method based on multi-physical field coupling is proposed. The vibration noise distribution is simulated and studied when the rated power frequency current is superimposed with different phase third harmonics. The simulation shows that under the rated power frequency superimposed with the third harmonic, the vibration noise of the series reactor increases significantly at 200Hz and 300Hz, while the variation at 400Hz is not significant. The variation and noise at 200Hz increase the most and become the main frequency of reactor vibration noise. The average increase in total sound pressure level under harmonics is 5.70 dB(A). Furthermore, the harmonic phase will affect the 100Hz vibration noise value. When the phase difference between the fundamental current and the third harmonic is 0°, the average increase in 100Hz noise is 0.867 dB(A). When the phase difference is 180°, the 100Hz noise decreases by 0.972 dB(A).