Objective:To investigate the crown-root an-gle of central incisor of early youth,and to analyze its correlation with cephalometric measurement of hard tissue. Methods:Forty-two malocclusion pations were enrolled to measure the crown-root angle of the 168 central incisors with MIMICS 10.0 software,and to measure three-dimensional and lateral cephalogram two-dimensional SPSS21.0 statistical software was used for the analysis of the correlationship between the crown-root angle and the results of cephalometric measurement. Results:In early youth,there is no significant correlation between the crm angle of the upper central incisor with the 8 cephalometric indexes. The cr angle of the upper central incisor is positively associated with the protrusion of upper central insicor,and is negatively correlated with SNA. The crm angle and the cr angle of the lower central incisor are positively associated with ANB and the protrusion of the lower central insicor. Conclusion:Some cephalometric indexes of hard tissue are related to the crown-root angle of central incisor of early youth,which has the clinical reference value.