The effect of crystal material, cavity length, pump power and other parameters on the width of Q-switched pulse is investigated, and a compact dual-wavelength laser with high efficiency based on Nd∶YVO4 crystal is developed. Master oscillator power amplifier (MOPA) structure is used in the laser system. A transverse fundamental mode of 1064 nm pulse with repetition frequency of 5 kHz, pulse energy of 400 μJ and pulse width of 1.1 ns is generated in the oscillator. Through the 878.6 nm zero-line pumped cascade amplifier, pulse energy and pulse duration turn to 2.72 mJ and 1.03 ns, respectively. A 532 nm green laser pulse with energy of 1.54 mJ, second harmonic generation efficiency larger than 56%, pulse duration shorter than 910 ps and peak power of 1.7 MW is obtained through the external frequency doubling by lithium triborate (LBO) crystal.