The invention relates to an optical output system with auto optical power control for an optical mouse. The optical output system comprises: a light emitting device, a driver and an auto power controller. The light emitting device is used for generating emitting light. The driver is used for driving the light emitting device. The auto power controller is used for outputting a control signal to the driver according to at least one input signals so as to control the power of the light emitting device at a predetermined range. According to the invention, the optical output system can output the stable power of the emitting light at a predetermined value within the predetermined range under various conduction and circumference by a feedback control. Furthermore, the optical mouse using the optical output system can work on various reflective surface.