The invention discloses a synchrocyclotron and a method for matching a high-intensity magnetic field thereof with a high-frequency frequency modulation curve, belongs to the field of particle cyclotron acceleration, and solves the problem that the magnetic field distribution of a flat magnetic pole does not match the high-frequency frequency modulation curve. The synchrocyclotron mainly includes amain magnet. The two magnetic pole faces with opposite magnetic poles of the main magnet are curved surfaces. The two magnetic poles are disposed centrally symmetrically. The method, based on the fine adjustment of an ideal frequency curve by the compensation of a high-intensity magnetic field and the large-range modulation of the high-frequency frequency curve by a rotary capacitor, repeatedly performs iteration to realize the optimum matching of the high-intensity magnetic field and the high-frequency frequency modulation curve, thereby ensuring the stability of the longitudinal phase spaceacceptance during an acceleration process, minimizing the beam loss in the synchrocyclotron and achieving a low level of excitation.