By using cascaded Wavelength Division Multiplexing (WDM),a fiber-based amplification of a fiber-pigtailed-pulsed diode laser is experimentally demonstrated.For a laser with 50 kHz repetition rate,20 ns pulse duration and 0.5 mW average power,the amplified output power up to 26 mW is obtained,which has a high signal to noise ratio of 25 dB.The corresponding gain is 17.1 dB.It offers a good pulse laser seed for high power laser amplifier.