By use of novel 879 nm Laser Diode (LD), quasi-three-level transition in Nd:GdVO4 crystal at room temperature is realized. For the crystal with Nd doped concentration of 0.2% and 3 mm×3 mm×3.8 mm in size, wavelength of 912 nm. The 912 nm laser with output powe of 2.5 W when the pump power is 33 W, corresponding to a slope efficiency of 11% with respect to the pump power and a slope efficiency 38% with respect to the absorbed pump power. For the crystal with Nd doped concentration of 0.2% and 3 mm×3 mm×5 mm in size. The 912 nm laser with output power of 3.0 W is obtained when the pump power is 33 W, corresponding to a slope efficiency of 16% with respect to the pump power and a slope efficiency 45% with respect to the absorbed pump power. For the acousto-optic (A-O) Q-Switched regime, average output power of 660 mW and pulse duration of 22 ns is achieved at the repetition rate of 10 kHz, the peak power is up to 3 kW. The relationship between lasing threshold and the length and Nd doped concentration of crystal are theoretically analyzed. The influence of reabsorption loss on laser′s operation is discussed and the saturation effect of reabsorption loss is observed.