The invention discloses a movable door mechanism of a high-tension switch cabinet. The movable door mechanism comprises a movable door and a drive mechanism, and the movable door is a side-by-side roller shutter door moving up and down and comprises an upper roller shutter plate and a lower roller shutter plate. Guide rails used for guaranteeing synchronous movement of the two sides and accuracy are mounted on two sides of the roller shutter door. The drive mechanism is used for driving a roller shutter door switch. The drive mechanism comprises mild steel wires, fixed pulleys, racks and gear shafts. One end of each mild steel wire is fixedly connected with an end of a middle position of the roller shutter door, is arranged along each guide rail, moves around the other end of each fixed pulley, and is fixedly connected with each gear shaft in a wound manner. The gear shafts are connected with the racks in a meshed manner and are respectively fixedly arranged at the bottom and the top of a breaker. The movable door mechanism of the high-tension switch cabinet is high in opening and closing accuracy, and the problem of asynchrony of two sides of the roller shutter door is avoided. Minimal force is required for opening the roller shutter door, travel of the roller shutter door is small, and complete isolation of a charged body is achieved. Safety of maintenance of the movable door mechanism is improved, and the movable door mechanism of the high-tension switch cabinet is safe and reliable, and flexible in operation.