The invention discloses an X-band 300w pulse power module. The module comprises a metal cavity structure; the metal cavity is divided into an upper cavity and a lower cavity; a radio frequency moduleis arranged in the upper cavity, and a power modulation module is arranged in the lower cavity; the radio frequency module comprises a first micro-strip dielectric slab and a second micro-strip dielectric slab in splicing; the first-stage power amplifying circuit, a second-stage power amplifying circuit and a third-stage power amplifying circuit in three-stage cascading and three isolators are arranged on two dielectric slabs; each power amplifying circuit is connected with one isolator. The power modulation module adopts a drain modulation way to modulate the drain electrodes of the three-stage power amplifying circuits and perform feed on grids. By adopting the three-stage cascading way, the use of each of a power synthesizer and a power amplifier is reduced, the size volume of the wholemodule is shrunk, and the integration is improved; furthermore, the output power is greatly improved through a drain pulse modulation way, the heating problem of the power module is avoided, and theperformance of the power module is improved.