An all fiber laser which is suitable for distributed optical fiber sensor is reported. The laser is based on the technique of master-oscillator-power-amplifier (MOPA), whose seed laser is a laser diode and amplifier is Er3+ doped fiber amplifier. The laser operates in wavelength of 1550 nm with the tunable repetition rate and the pulsewdith, and the 3 dB width is less than 0.2 nm. The maximum peak power 1.1 kW of laser pulse is obtained, and the power of amplified spontaneous emission (ASE) in the output pulse is less than 10% in all condition.