Synchronous device for sliding plug door of passenger car

The utility model relates to a synchronous device for a sliding plug door of a passenger car. The synchronous device comprises a rail box which is fixedly arranged on a passenger car body, and a sliding drive small car arranged in the rail box, wherein a door connecting plate on a door frame is fixed on a passenger car door body, and the bottom of an end plate on a left car body of the sliding drive small car is provided with a vertical shaft drive plate which is provided with a drive groove. A synchronous vertical shaft arranged on the passenger car body is arranged under the rail box, an upper swing arm is fixed on the upper portion of the synchronous vertical shaft, a lower swing arm is fixed on the lower portion of the synchronous vertical shaft, a roller is arranged on the head portion of the upper swing arm, and the roller is installed in the drive groove. A horizontal sliding rail is arranged on the lower portion of the passenger car body, a roller is arranged on the head portion of the lower swing arm, and the roller is arranged in the horizontal sliding rail. The synchronous device achieves synchronous motion of opening and closing of a passenger car door, and eliminates faults during working of the passenger car door.