To achieve high-power blue semiconductor laser outputs， the packaging technology of blue light bars was studied herein. First， high-power gallium nitride （GaN） blue semiconductor laser bars were encapsulated using gold-tin hard solder. A copper-tungsten transition heat sink was used as a buffer layer to suppress the residual stress between the copper heat sink and GaN laser chips. The chips were eutectic bonded onto the copper-tungsten transition heat sink using a high-precision SMT machine. Because the quality of the SMD directly affects the output characteristics of the device， the focus was on analyzing the impact of the bonding temperature and pressure of the SMD machine on the device. The experimental results reveal that， when the bonding temperature of the mounter is 320 °C， bonding pressure is 0.5 N， and bonding time is 40 s， the solder layer interface cavity is the smallest， thermal resistance is the lowest （0.565 °C/W）， and threshold current is also the lowest （4.9 A）. When the injection current is 30 A， the maximum output optical power is 32.21 W， and the maximum solar-cell efficiency reaches 23.3%. Therefore， after optimizing the bonding temperature， bonding pressure， and bonding time， the technical solution of using gold-tin hard solder to eutectic bond blue semiconductor laser chips onto copper-tungsten transition heat sinks is an effective way to achieve high-power operation of blue semiconductor laser bars.