High-power laser diode-pumped solid-state lasers are replacing flashlamp-pumped solid-state lasers and are widely used in industries. A laser diode-side-pumped Nd:YAG laser is reported. Output laser power of 360 W and stability of ±1% are obtained though the series-oscillation resonator using two laser diode pump modules. There are totally 30 diode bars used in each module and 5 diode bars are placed around the NdYAG rod. There is a flow tube between the diodes and the NdYAG rod, cooling water flows inside the tube and brings out heat. A flat rear mirror and a flat output coupler are used as laser resonator. The structure and output characteristics of the laser are studied in detail. It is shown that the laser is compact and reliable with high conversion efficiency and long life extension.