[Objective] To investigate the effect of metabolic obesity on bone metabolism in juvenile (17 weeks) and adulthood (27weeks) male SD rats. [Methods] Five week old male SD rats were randomly divided into normal control diet group (ND group) or high fat diet group (HFD group) according to random number table. After metabolic obesity models were successfully established, Type 1 procollagen N-terminal propeptide (P1NP), type 1 collagen C-terminal peptide (CTX-1)and the serum calcium and phosphorus levels were detected in different periods. Three-point bending test was performed to observe changes in bone strength. MicroCT examination was conducted to observe changes in bone microstructure. [Results] 1.Compared with ND group（578.82 ± 23.96pg/ml）, P1NP（426.57 ± 35.22 pg/ml） was decreased (P<0.01), and CTX-1 （88.44±8.73 vs 142.60±13.74 pg/ml）was increased (P<0.05) in 27 week old HFD group. 2. Trabecular bone markers such as Tb. vBMD,（0.135±0.011 vs 0.105±0.007 g/mm3）、Tb.BV/TV（34.64±2.766 vs 27.16±1.808 %）、Tb.N（2.454±0.145 vs1.907±0.143 1/mm ）were decreased, Tb. Sp（0.329±0.014 vs 0.538±0.068 um）was increased in 17 week old HFD group compared with ND group. The change trend of the above parameters was more obvious in 27 week old HFD group (P<0.01). 3.The maximum load（300.46 ± 7.13 vs 242.54 ± 11.78 N ）, maximum fracture load（285.58± 10.09 vs 227.44 ± 14.17 N ）, ultimate tensile strength（11.24±0.28vs 9.07 ± 0.66 MPa ）, stiffness（779.90± 41.99 vs595.14 ± 31.13 N/mm ） and energy absorption（192.89± 13.42 vs 138.61 ± 12.67 N*m ） were decreased (P<0.01 or P<0.05) in 27 week old HFD group compared with ND group. [Conclusion] Metabolic obesity can reduce marker of bone formation and increase marker of bone resorption. Bone microstructural changes begin in adolescents, and bone microstructural damage increases and bone strength decreases in adults.