Abstract: The chaotic control of output of a semiconductor laser is studied. A 1.55 μm semiconductor laser is entered into chaotic motion by current modulation. And then, the adaptive control scheme is used to control the chaotic motion of this laser system. The advantage of this method is that the stable output can be obtained if only the controller is selected according to the control target. Present research results have many helpful values to improve the speed of control, flexible adjustment of laser output power as well as efficiency of energy transformation for real laser system.