The present disclosure relates to a joint assembly and a robot comprising a joint assembly, wherein the joint assembly comprises a brake casing, wherein the axle is rotatable around the rotation axis relative to the brake casing, and a brake ring being coaxial with the axle and positioned at the first axial position. An internal diameter of the brake ring in a braking mode is equal to or less than the first axle diameter, and the internal diameter of the brake ring in a non-braking mode is more than the first axle diameter.