Abstract: A center-mounted control system for a bicycle includes a torsion detector, a torque transducer, first and second wireless transceiving units, and a control unit. The torsion detector is sleeved on a crank shaft and detects a torque signal of the crank shaft and transmit the detected torque signal to the torque transducer; the torque transducer is fixedly connected to the torsion detector and senses the torque signal transmitted from the torsion detector and sends the torque signal to the first wireless transceiving unit; the control unit receives and processes the torque signal and controls an electrical motor according to the processed torque signal; and a first clutch of the bicycle is sleeved on the crank shaft and is fixedly connected to one end, close to a chain ring, of the torsion detector, and the first clutch of the bicycle is fixedly connected to the chain ring.