A differential capable of automatically restricting a differential ratio and increasing torque comprises a container. A differential housing is provided in the container. The differential housing is internally provided with a planetary gear, a planetary shaft, a left half axle gear, and a right half axle gear. The planetary gear is provided on the planetary shaft, and the planetary gear engages with the left half axle gear and the right half axle gear, respectively. The differential housing comprises a left housing and a right housing engaging with each other. A ring gear is provided at the outer circumference of an end of the left housing engaging with the right housing, and a bevel ring gear is provided at the outer circumference of an end of the right housing engaging with the left housing.