Through designing composite heat sink of vertical cavity surface emitting laser based on diamond Micro groove structure, using different materials thermal conductivity to optimize the problem of vertical-cavity surface-emitting laser array non-uniform heat flux distribution leading to non-uniform temperature improved the reliability of laser array due to the center heat concentration and optimized the output power of the laser array. Building 3-D thermoelectric coupling model which is based on finite element analysis method studied the vertical cavity surface emitting laser array element configuration influence on the laser unit thermal crosstalk effects. And studying and analyzing the diamond composite heat sink in the pore shape and location of the change on the influence of the internal temperature of the semiconductor laser optimized the laser light. Compared with the traditional packaging structure of diamond heat sink, the vertical cavity surface emitting laser array is improved by using diamond composite heat sink., the temperature difference of laser element is reduced by 29%.