A high power portable femtosecond fiber laser system is demonstrated. This system uses semiconductor saturable absorb mode-locked fiber laser as the seed source and selects the wavelength through the fiber Bragg grating. The seed light output by the oscillator enters the main amplifier system after being pre-amplified by two-stage single-mode ytterbium-doped fiber and first-order double-clad ytterbium-doped fiber. The main amplifier uses a large mode field of ytterbium-doped photonic crystal fiber to amplifier, and effectively reduces the effect of nonlinear effect on the pulse by controlling the nonlinear accumulation in the amplification process. An acousto-optic modulator is added to make the output repetition frequency adjustable, and the output pulse is compressed through the transmission grating to obtain the laser output. The final output has an average power of 1.34 W, a repetition rate of 300 kHz, a working wavelength of 1030 nm and a pulse duration of 202 fs, and the corresponding single pulse energy is 4.5 μJ, peak power is 22 MW. The complete laser system is portable, stable, and cost-effective, and can be widely used in production.