Semiconductor laser cooling is to provide a low thermal resistance path between heat source and heat sink. Its main purpose is to reduce the external thermal resistance (resistance between the laser chip and the cooling space) to maintain a low temperature gradient and good thermal contact between the heating laser chip and cooling surface. Experimental methods are used to solve the problem of contact resistance according to the study object. Based on the single-chip combined beam module, a overall thermal resistance is analyzed gradually, software simulation and the frequency with red shift method are described for the thermal resistance of laser diode measurement. Single-chip combined beam module overall thermal resistance is less than 0.25 ℃/W. The cooling modules can be used in the 100 W-class semiconductor laser cooling requirements.