The invention relates to a variable speed wheel-disc integrated mid-motor in an electrical bicycle. The central motor is arranged on a five-way joint on a frame of the electrical bicycle, and can be driven electrically, manually, both electrically and manually or respectively electrically and manually without influence. The motor is low in energy consumption, stable and reliable in force transmission and high in climbing capability in motions. The motor comprises a left screw cap, a first bearing, a motor center shaft, a first screw, an inner motor end cover, stator silicon steel sheets, a second bearing, a stator inner core, a third bearing, a first one-way clutch, an internal gear, a planet carrier, a fourth bearing, a chain wheel, a second one-way clutch, a second screw, a fifth bearing, a right lock nut, an internal gear shaft, planetary gears, an outer motor end cover, magnetic steels and a chain wheel fixing ring.