A virtual reality-based eyeball tracking method and system are provided. Eyeball calibration data is presented to eyes of a user through a display, and then a binocular pupillary distance of the user is obtained through the eyeball calibration data. A left tracking camera captures reflected infrared light of a turned on left infrared light source, and a right tracking camera captures reflected infrared light of a turned on right infrared light source, so that tracking data of one eye is formed in each specific frame. Tracking data of the other eye in the specific frame is calculated according to the binocular pupillary distance and the tracking data of one eye. The tracking data of one eye and the tracking data of the other eye are arranged according to a time sequence of the specific frame to form binocular tracking data so as to complete eyeball tracking.