The design of digital contr ol system of LD driver circuit, including the optic power control system and the temperature control system is introduced. The singlechip is the core, combined with peripheral circuit, with the digital control instead of the analog circuit control. It is easy to control, and the precision is high. The singlechip is the core of optic power of control system , and peripheral circuit includes power sampling and current driver. The PD control algorithm is used to control the electric current. So it can control the optic power of LD. The PD parameters are tuned in engineering experiments. Mathematics model is built to realize software control. In order to improve the control precision, the optic power is divided into 9 parts, and PD parameter of each part is adjusted. The power error of LD can be controlled within 0.02 W. The precision of the designed driver circuit is high. The circuit is well-real time, and reaches the requirement of design.