The utility model discloses a disconnector for a transformer. The disconnector comprises a housing with a square recessed chamber, which is divided into three independent compartments by two separator plate integrated with the housing, and a binding post is arranged on each side of each compartment. The binding post is riveted on the housing, and is divided into a wiring portion and moving contacts with the riveting point as the separation part. The wiring portion extends to the external of the housing and is provided with a wiring hole, and the moving contacts extend into the compartments. Each of the two separator plates is provided with an opening, and the openings of the two separator plates face each other to form a channel. The disconnector further comprises a sliding block arranged in the housing, and the sliding block is erected among the compartments and is slidable in the channel. Two static contacts are arranged in each compartment and symmetrically connected to the two sides of the sliding block. An each moving contact corresponds to one static contact.