Objective To evaluate the accuracy and reliability of cone-beam computed tomography (CBCT) in measuring alveolar bone height.Methods Eight human cadaver head samples were scanned with CBCT technology.Measurements were made on each tooth from the cusp or the middle point of incisal margin to the cementoenamel junction (T-CEJ),from the cusp or the middle point of incisal margin to the alveolar bone margin (T-BM) and from the cementoenamel junction to the alveolar bone margin (CEJ-BM) along the long axis of the tooth.Measurements were made both in the CBCT images and on the real samples.The paired-t test was made between the two different measurements to evaluate the accuracy of the CBCT measurements.And 210 sites from 6 samples were measured.The Interclass correlation coefficient (ICC) was calculated to evaluate the reliability of CBCT measurements.Results The values of CBCT measurement were smaller than those of the direct measurement.Significant difference was found in the values of T-BM and CEJ-BM.The mean deviations were - 0.268 mm and - 0.208 mm.The values of T-CEJ showed no significant difference and the mean deviation was -0.041 mm. The ICC of all the measurement was above 0.96.Conclusions Significant difference was found in the measurement of alveolar bone height between CBCT and direct measurement. But the mean deviation was very small. The CBCT measurement showed high reliability.