The invention relates to a coaxial high-power microwave generator based on a nonlinear transmission line. The generator comprises a first fixing flange, a second fixing flange, an outer conductor of the transmission line, an inner conductor of the transmission line, a front segment of a nonlinear ferrite magnet ring, a rear segment of the nonlinear ferrite magnet ring, a solenoid, a solid dielectric medium and a nylon fixation device. The front edge of input high voltage pulses is sharpened, an input pulse magnetic field is mutually coupled with the magnetic moment of a non-linear material to generate and output high-frequency microwave oscillation signals, and the generator is characterized by high repetition rate, high versatility, low using cost, convenient and safe performance and the like.