One kind of conductively-cooled,double-edge-bounce-pumped and pulsed Nd:YAG double-stage slab laser amplifier is reported.When the amplifier operates in pulsed condition,its high efficiency,good beam quality,compactness,weak thermal effects and high scalable gain are proved by the tests of the input-output relationship,beam quality and thermal effects and so on.The pulsed laser generated by a seed injected single-frequency oscillator,whose power is 1.1 W,pulse duration is 11.3 ns and beam quality factor (M2x,M2y) is 1.2,is amplified by the amplifier at the repetition frequency of 125 Hz and high-beam-quality output laser,whose power is 24.1 W,pulse duration is 8.9 ns and beam quality factor M2x is 1.53,M2y is 1.27,is obtained.Experimental results show that this kind of laser amplifier has great potential in the application of space detection.