Abstract: Objective To investigate the symmetry of upper lip and establish the normal value in three-dimensional directions for adolescents. Methods Cone Beam computed tomography and frontal photographs from 104 orthodontic patients were included. The thickness of upper lip was measured by MIMICS10.0, while the lip width, height of vermilion and upper lip were measured by digital photography-computer aided method. A total of 30 landmarks were selected, 23 lines were measured. Data were analyzed by SPSS17.0. Results Most of the measured values of lip in male were statistical different from female, and moreover, all the distances were larger in male. There was a tendency of growth on height, width and thickness of the basal upper lip, but the thickness of labial arch was thinning with the growth of age. The study of discrepancies in upper lip showed 2mm asymmetry on the width, 0.4mm on the vermilion height of christa philtrum. Besides, when symmetric analysis was based on the percentage, the discrepancy on width was largest, thickness intermediary and height least as well. Conclusion Normal three dimensional reference values for upper lips were estimated. All the values were higher in male than female. With the growth of age the thickness of labial arch was thinning, other values tended to largen. Besides, the discrepancies of upper lip were primarily on the width.