A motor structure includes a stator and a rotor. The stator includes a coil assembly which includes a ring-shaped slot having an inner periphery on its inner side and an outer periphery on its outer side away from the inner periphery, a plurality of first teeth mounted around the inner periphery of the ring-shaped slot, and a plurality of second teeth mounted around the outer periphery of the ring-shaped slot; wherein each of the first teeth is arranged to partly fall behind or exceed the corresponding one of the second teeth, and a coil wound in the ring-shaped slot. The rotor includes a circular magnet located above the coil.