The utility model provides a rotary mechanism of a middle handrail of a driver seat and a passenger seat of a car. The turnover mechanism of the middle handrail of the driver seat and the passenger seat of the car comprises a support foot, a support arm, a locking foot, a foot locking shaft pin and a foot locking press spring. The locking foot is connected with the support arm through the foot locking shaft pin, and the foot locking press spring is connected between the locking foot and the support arm. Arc-shaped tooth faces are arranged on the backs of the two sides of the front end of the locking foot, wherein a copper pin and a copper press spring are arranged in one side of the locking foot. Arc-shaped tooth bars use to be meshed with the arc-shaped tooth faces on the locking foot are respectively arranged on the backs of the two sides of the support foot, a guide structure guiding the copper pin to move is arranged on the end face of one side of the support foot. According to the rotary mechanism of the middle handrail of the driver seat and the passenger seat of the car, one copper pin and one copper pin press spring are additionally arranged on one side of the locking foot, the guide structure of the copper pin is additionally arranged on one side of the support foot, the locking foot is driven to achieve the automatic separation and reunion in the rotary process, rotation of the handrail does not need external forces, up and down repeated rotation of the handrail can be achieved, and a rotary gear of the middle handrail of the driver seat and the passenger seat of the car can be opened automatically.