The invention relates to a system for acquiring and controlling an accurate boost signal of a rear shaft of an electric boost bicycle. The system comprises a strain foil, a Hall sensor, a boost ratio adjusting button arranged in a handlebar of the electric boost bicycle, and a PCB circuit board arranged on a brushless motor of the electric boost bicycle, wherein the strain foil is stuck on the rear shaft of the electric boost bicycle, namely the shaft of the brushless motor; the Hall sensor is stuck in the circumferential direction of a motor shell of the brushless motor; the PCB circuit board is stuck in the radial direction of the motor shell of the brushless motor; the PCB circuit board comprises a signal controller, a brushless motor controller, a first socket and a second socket; and the signal controller comprises a signal amplifying circuit integrated on the PCB circuit board, a pulse shaping circuit, a voltage source, an integral circuit, and a singlechip. Therefore, the invention provides the boost signal acquisition and control system of the electric boost bicycle, which has no abrasion, adjustable and accurate boost ratio, smooth and stable operation, and safety.