Abstract: The present invention discloses a shaft rotating constant-width curve double-stator multi-speed motor, comprising a rotor (5), an inner stator (19), an outer stator (3), sets of sliders (22) mounted on the rotor, a left end cover (6) and a right end cover (1), a curve of an external surface of a front portion of the inner stator (19) and a curve of an internal surface of the outer stator (3) are two similar curves which are smooth and closed, wherein oil distributing ports in outer stator (20) are opened on the outer stator (3) in the number of 2×n (n is the number of actions), oil distributing ports in inner stator (24) are opened on the external surface of the front portion of the inner stator (19), and the inner stator (19) is mounted in the rotor (5). The multi-speed motor of the present invention works stably and has a small volume, a light weight, a high efficiency and a large specific power.