Objective This study aimed to explore the development of the frontal sinus in Han people by computed tomography (CT) images, and to analyze the growth pattern according to age. Methods It was retrospectively analyzed for CT data of 285 patients aged from 1 to 25 years. Three-dimensional reconstruction of bilateral frontal sinus was performed by Mimics software. The development time of frontal sinus pneumatization was observed. The height, width, depth and volume of developing frontal sinus were measured, and the data were analyzed statistically. Results Frontal sinus pneumatosis was observed as early as in children aged 2 years, and its size increased with age, with a surge period in 4~8 years and 10~14 years, and developed after 17 years. The volume of the left frontal sinus was statistically significantly larger than the right. Frontal sinus was bigger in males than in females, but no statistically significant difference was observed under 17 years old. After frontal sinus reached adult levels (17 years old), there was a statistically significant difference between genders (P<0.05), except for the width of the right frontal sinus (P=0.085). Conclusion The normal development of frontal sinus was understood by CT 3D-reconstruction,which will provide a reference for the diagnosis and treatment of frontal sinus diseases in Han people of different ages.