The invention discloses a method for measuring the sound insulation volume of an electric reactor acoustic enclosure. The method includes: directed at each plane of the electric reactor acoustic enclosure, placing an acoustic signal generator at a first sound source position in the electric reactor acoustic enclosure respectively to generate acoustic signals of preset frequency and preset acousticpower level, and respectively measuring a sound pressure level value of the first measurement position symmetric with the first sound source position based on a current plane, thus obtaining the corresponding sound pressure level values of all planes; placing an acoustic signal generator at a second sound source position outside the electric reactor acoustic enclosure to generate acoustic signalsof preset frequency and preset acoustic power level, and measuring the sound pressure level value of a second measurement position in a horizontal distance of a second preset threshold to the secondsound source position; subjecting the sound pressure level values corresponding to all the planes to arithmetic averaging to determine an average sound pressure level value; and utilizing the sound pressure level value of the second measurement position and the average sound pressure level value to calculate the insertion loss of the electric reactor acoustic enclosure at preset frequency, i.e. the sound insulation volume of the electric reactor acoustic enclosure.