A practical pulsed fiber laser based on master-oscillator power amplifier (MOPA) architecture is reported. A laser diode (LD) driver based on high-speed MOFSET is used as seed laser. The single mode double-cladding fiber is used in the two stages as preamplifier, and the double-cladding fiber is used in the booster. The laser can generate narrow pulse width output at repetition frequency of up to 600 kHz. At repetition frequency of 125 kHz, amplified laser with average power of 2.4 W and pulse width of 10 ns is generated. This robust pulsed laser is a good candidate for space-based 3D imaging lidar.