The utility model discloses a long-life active sound barrier for a transformer station. The sound barrier comprises a T-shaped passive sound barrier; and a time control switch, a loudspeaker, an error sensor, a multichannel active soundproofing controller and a reference microphone are fixed at the top of the T-shaped passive sound barrier, wherein the time control switch is connected with a power line of the multichannel active soundproofing controller, and the reference microphone, the error sensor and the loudspeaker are connected with the multichannel active soundproofing controller via audio transmission lines. According to the utility model, the active sound barrier is used for treating noise of the transformer station, thereby avoiding that the noise reduction effect is influenced because that the height of the sound barrier is limited by the heights of inlet/outlet wires of a main transformer; and according to different noise standards in day and night, the time control switch is used to control starting of the active soundproofing part, thereby greatly prolonging the service life of the active sound barrier.