The invention relates to a light current scanning system, which comprises a laser generation device, a focusing device, a displacement adjustment device, a bias voltage supply device and a measuring device. The laser generation device is used for emitting lasers; the focusing device is used for focusing the lasers to the surface of a to-be-measured sample in the displacement adjustment device; thedisplacement adjustment device is used for driving the to-be-measured sample to enable the lasers to be irradiated to different parts of the surface of the to-be-measured sample; the bias voltage supply device is used for providing the voltage for the to-be-measured sample; and the measuring device is used for measuring a signal of a current flowing through the to-be-measured sample.