An automatic parking system includes a smart key recognizing sensor recognizing a smart key positioned in a first area, a sensor device detecting parking areas depending on a size of a subject vehicle if the smart key is recognized and a controller controlling the subject vehicle to be parked in an optimal parking area among the parking areas, in which the sensor device may detect the parking area in consideration of a length and a width of the subject vehicle and the controller may calculate a moving path between a current position of the subject vehicle and the optimal parking area.