The characterization of an arched diode-side-pumped Nd∶YAG laser was reported. A concentric-pumping and concentric-cooling close configuration was used for the laser. The pump light distribution and temperature profile were calculated and optimized. Influence of the laser diode chirp and sag on the laser output, the effect of thermal birefringence on the laser Q-switch output and laser output under different resonator length and different cavity have been studied. A maximum output of 135 mJ in multimode Q-switch operation is obtained with pumped energy 735 mJ (marked value). The pulse width is 7.6 ns and the full divergence angle is smaller than 1.5 mrad. The slope efficiency is 44.3%. The optical-optical efficiency is 18.4%.