Method for automatically measuring pupillary distance includes extracting facial features of face image, a head current center indicator is shown/displayed based on facial feature extraction, elliptical frame and target center indicator are shown, a first distance between head current center indicator and target center indicator is calculated to see if below a threshold range, then allowing head current center indicator, elliptical frame and target center indicator to disappear. Card window based on facial tracking result is shown. Credit card band detection is performed to see if located within card window. Card window then disappear. Elliptical frame of moving head and target elliptical frame are shown. Elliptical frame of the moving head is aligned with the target elliptical frame and maintaining a correct head posture. If elliptical frame of moving head is aligned with target elliptical frame, then allow them to disappear from view, and performing a pupillary distance measurement.
