Objective To analyze the imaging manifestations of third molar（M3） in aged 11, and to explore the relationship of development between M3 and second molar（M2）, canine（C）. Methods A total of 399 cases, aged 11, of West China School of Stomatology in June—August 2010 were selected as the imaging database. The M3, M2, C on the panoramic images were observed and the development degree in 399 was divided. And then the correlation analysis was done. Results 45.5% of M3 in aged 11 was in stage C. 30.8% of M2 was in stage F. 36.1% of C was in stage G. The development of M3 appeared earlier in girls than in boys, and earlier in the mandible than in the maxillary． There was no significant difference between the left and right side. The correlation coefficient between M3 and
M2 was 0.437, and the correlation coefficient between M3 and C was 0.132. Conclusion The general trends of the developments of M3 and M2, C were the same. The development of M3 can be used to describe the development of M2 and C, according to the close relationship in radiograph．
