Cascaded fiber amplifier with high repetition rate, short pulse-width all-solid-state laser seed can achieve high output power. The average output power that is close to continuous wave (CW) performance is easily achieved for CW-pumped, high-repetitively Q-switched Nd∶YVO4 laser. The major factors influencing the pulse energy and pulse-width in acousto-optic (AO) Q-switched laser are analyzed, and the resonance parameters are optimized. The Nd∶YVO4 laser end-pumped by a fiber-coupled laser diode (LD) is reported, and A-O Q-switched 1064 nm laser with repetition rate larger than 100 kHz and pulse-width shorter than 20 ns is achieved. At the pump power of 5.7 W, laser seed with pulse width of 15.3 ns and pulse repetition rate of 150 kHz is acquired. The final output power of 20 W is achieved with the fiber amplifier.