Aiming at the problems of poor detection accuracy in the existing high-frequency partial discharge detection methods of electrical equipment, a high-frequency partial discharge detection technology of electrical equipment based on modulated laser phase is proposed in this paper. The frequency domain window width is determined by Gaussian error function to complete the acquisition of high-frequency partial discharge signals of electrical equipment. According to the characteristics of sinusoidal or cosine signal of local discharge narrow-band interference signal of electrical equipment, the Fourier series method is used to suppress the narrow-band interference and extract the characteristics of discharge interference signal. On this basis, the high-frequency partial discharge detection of electrical equipment is completed by synchronously calibrating the high-frequency signal and separating the laser phase pulse. Experimental results show that the high frequency partial discharge detection technology of electrical equipment designed in this paper effectively improves the accuracy of high frequency partial discharge detection of electrical equipment, and the detection time is always less than 4 min.