The invention discloses an optoelectronic-oscillator-based X-band high-speed swept signal generation device and an optoelectronic-oscillator-based X-band high-speed swept signal generation method. The device comprises a swept laser, a phase modulator, an erbium-doped optical fiber amplifier, a variable optical attenuator, a dispersion compensation module, a circulator, an optical fiber, a polarization controller, an optoelectronic detector, a microwave signal amplifier and an oscilloscope or a frequency spectrograph. According to the device and the method, the optoelectronic-oscillator-based X-band high-speed swept signal generation method is proposed for changing structural design that a microwave swept signal is generated by virtue of the development and innovation of a novel optoelectronic technology, particularly microwave photonics, and the swept laser is used for tuning a loop parameter to obtain an X-band microwave swept signal with continuously adjustable oscillation frequency; meanwhile, the dispersion compensation module is used for realizing a corresponding optical fiber delay line function in a conventional optoelectronic oscillator, so that the short frequency switching time interval of the generated microwave swept signal is ensured, and a foundation for the application of the device and the method to microwave swept signal generation is laid by high scanning speed.