An all-fiber femtosecond pulses amplification system was researched. A nonlinear amplifying loop mirror resonator delivering broad-spectrum seed pulses was employed, and the fiber chirped pulse amplification technique was adopted to supress the accumulation of nonlinearity during the power amplification process; Besides, combining the fiber fusion spliced technique of the double-clad fiber and large-mode field photonic crystal fiber, the main amplification system generated high-quality picosecond pulses with 1030nm central wavelength and 16.9W average power. After the spatial grating pairs’dispersion compensation, the pulses duration had been compressed to 324fs with energy of 12.2μJ, corresponding to a peak power of about 26.4MW. All-fiber structure was realized by using special polarization maintaining fiber fusion technology instead of free-space coupling, the optical path structure and stability of environment was further optimized. All the ways mentioned above are expected to improve the process of high-energy fiber laser industrialization and adaptability in the complex environment.