Abstract: Objective: To observe histomorphology changes of condyle and differences between young and adult through mandibular advancement intermittently so as to provide the opportunity and strategy of mandibular advancement. Methods: Mandibular advancement model was established on 4 weeks old and 8 weeks old BABL/c female rats. The TMJ samples were harvested at the 14th and 28th days and stored for Trap staining and Godener trichrome staining and Micro-CT scan. Results: Compared with those at 28th day of the 8-week-old group, the at 28th day of the 4-week-old group was as follows: BV/TV and TB.Th decreased; Tb.Sp increased(P<0.05); TB.N was not different(P>0.05). Compared with those at 14th day of the 8-week-old group, the at 14th day of the 4-week-old group was as follows: the number of Trap positive osteoclasts and the number of osteoblasts were all increased(P<0.05). Compared with those at 28th day of the 4-week-old group, the at 14th day of the 4-week-old group was as floows: the number of Trap positive osteoclasts and the number of osteoblasts were all increased(P<0.05). Conclusion: Bone remodeling on rats is related with mandibular advancement and the has significant differences between different ages.