A power-generating illumination device for the bicycle comprises comprising at least one permanent magnet disposed onto wheel spokes so as to form a rotor, an induction coil assembly mounted onto a fork for forming a stator, such that during the rotation of the rotor, the induction coil assembly may be cut by magnetic lines of force to generate electrical energy for being outputted to a light-emitting unit, characterized in between the induction coil assembly and the light-emitting unit is provided with a control unit at least including a wave detector, a wave filter, and a current limiting resistor so that the wave detector, the wave filter, and the current limiting resistor are connected together to form a loop, thereby detecting and filtering polarity of voltage of the generated electrical energy and lowering the resonating frequency to maintain the service life and illuminative brightness.