The invention discloses a pulse width adjustable and repeated frequency adjustable narrow line-width all-optical-fiber ultra-short pulse amplification system, belongs to the technical field of laser, and discloses a pulse width adjustable and repeated frequency adjustable narrow line-width all-optical-fiber ultra-short pulse laser amplification system. The amplification system comprises a narrow line-width picosecond mode-locked laser oscillator, a single-mode optical fiber amplifier, a first optical fiber isolator, an optical switch, a plurality of optical fiber circulators, an optical fiber coupler, a first double-clad optical fiber amplifier, a second optical fiber isolator, an acoustic optical modulator and a second-clad optical fiber amplifier which are connected in sequence, wherein the optical switch can realize multi-way switching; the optical fiber circulators are connected with chirped fiber gratings; the acoustic optical modulator can be used for emitting different repeated frequency radio frequency signals; an input end of each optical fiber circulator is connected with different output ends of the optical switch respectively; each optical fiber circulator is connected with one chirped fiber grating; the dispersion coefficient of each chirped fiber grating is different. According to the system, high-energy ultra-short pulse laser of different pulse widths and different repeated frequencies can be output as required.