A continue wave laser diode driver controlled by single-chip microcomputer (SCM) is presented. It can work in three operating modes——automatic current control (ACC), automatic power control (APC) and automatic voltage control (AVC). The sweep current can attain the level of milliampere from 0A to 2A, and the temperature could also attain to ±0.1 ℃ with PI control and the thought of integral separation. Complete laser diode protection is provided including independent current limit and power limit settings, output off shorting circuits and a slow turn on sequence. The results show that this driver has a lot of advantages, such as high intelligence, good noise suppression, high stability and convenience.