Objective To explore a more accurate method in the area measurement of curved surface such as orbital rim. Methods Twenty-six NF1 patients were acquired. CT scan on both sides of the orbit and 3D reconstruction were completed. The orbital rim area was measured in approximate coronal plane and 3D curved plane respectively. The data were statistically analyzed. Results On average, the data of the plane method were underestimated, compared with the 3D method. There was statistical difference between the two groups. Conclusion The measurement in 3D curved plane is accurate, stable and easy to operate, which can replace the measurement in approximate coronal plane.