Disclosed is a mobile noise reduction apparatus used for a main transformer of a transformer substation. By virtue of a dual-layer resonance sound absorption plate (6) arranged on a supporting frame on the outer side of a main transformer (12), the noise and the like of the main transformer are lowered effectively, and important significance to noise control of the transformer substation is achieved; and the mobile noise reduction apparatus has the characteristics of simple structure, convenience in operation and the like, has certain economic benefits and is suitable for large-range popularization and application.