A rotating car seat mechanism includes a seat base, a sliding plate, a rotating plate, a guiding socket plate, an axle defining an axis of rotation and a cylindrical pivot rod. The sliding plate is placed inside a car, allowing an upper end of the cylindrical pivot rod to be positioned at the exit of the guiding socket, further enabling the rotation out of the car door and sliding the cylindrical pivot rod into the guiding socket. Due to the path defined by the guiding socket customizing the movement of the cylindrical pivot rod, the rotating plate not only rotates on the axle, but also drives the axle forward. After applying a suitable degree of motion, the rotating plate exceeds out of a narrow space of the car, whereas an opposite amount of motion enables the rotating plate to return to the original point.