The invention discloses an auxiliary automobile seat which comprises a mechanical unit and a power supply unit. The mechanical unit comprises a seat body, transmission modules, a bottom board and a joint connector. The bottom board is horizontally arranged. The joint connector is arranged at one end of the bottom board. The transmission modules are horizontally fixed to the bottom board and each comprise a sliding block, a guide rail and a motor, wherein the sliding block and the guide rail are matched with each other. The seat body is arranged above the transmission modules and connected to the sliding blocks of the transmission modules. The power supply unit is electrically connected with the motors and controls the sliding blocks to move. Compared with the prior art, the auxiliary automobile seat is provided, the seat body is driven by the transmission modules to move back and forth so that the seat body can stretch and retract automatically, the structure is simple, and operation is convenient.