The influence of heat sink and ceramic substrate on the performance of semiconductor laser array with back-cooled packaging structure was analyzed. The equivalent resistance of the heat sink of composite diamond was reduced and the matching of thermal expansion coefficient was realized by rasterized thick copper filling technology. Using heat sink and ceramic substrate embedded welding technology, the heat dissipation ability and stability of the packaging structure was improved. Then the sample of 5Bar chip array with 0.4mm spacing was fabricated, and test results indicate that at 70℃, 200A and 1% duty cycle, the output power and the electro-optic conversion efficiency can reach 1065W and 59.2%, respectively. The sample shows good reliability in the 1824hours life test under high temperature and high current.