The effects of indium solder coating and reflow soldering technique on diode bar soldering state are studied. Based on numerical simulation and experimental research, the design of cooler structure is optimized and the copper micro channels water cooler with low thermal resistance, low pressure is fabricated, which can meet the needs of cooling diode laser with more than 60W thermal dissipating power. A CW linear array diode laser with output power of 40 W, wavelength of 808 nm, spectral width of less than 2 nm, E O efficiency of 40% is achieved by packaging experiment. The experiment of pumping Nd∶ YAG solid state laser by the diode is carried out. The output power is 11.8 W with single transverse mode and 30% optical optical efficiency at pumping power of 40 W.