The output stability and life of laser devices are directly affected by the performances of diode laser drivers. A design method of 100 W high-power fiber coupled diode laser module driver is described under 40 ℃ high-temperature environment, which includes the design of constant-current sources, a temperature controller with TEC double directions, corresponding MCU controllers and protection circuits. The following functions of diode laser driver are obtained, i.e. the output current can be continuously adjusted from 0 A to 45 A, the current control accuracy is better than 1%, the range of temperature control is +15 ℃~+35 ℃ and temperature control precision is 0.5 ℃.