An eyeball tracking system is provided, which includes: an illumination light source, configured to transmit an illumination light ray to a beam scanner; the beam scanner, configured to project the illumination light ray onto an entrance pupil optical apparatus; the entrance pupil optical apparatus, configured to reflect, reproduce, or refract the illumination light ray, so that the reflected, reproduced, or refracted illumination light ray illuminates an eyeball; a photoelectric detector, configured to: collect a receive optical power value of an eyeball reflection light ray, and send the receive optical power value to a controller; and the controller, configured to: receive the receive optical power value sent by the photoelectric detector, determine, based on the receive optical power value, an optical power reference value, and determine a current gaze direction of the eyeball based on the optical power reference value.