Abstract： Objective To study the correlation of the bone mineral density (BMD) and the body composition components of body mass index (BMI), FAT and LEAN in Chinese obesity. Methods There were 150 cases in obesity group diagnosed by BMI, including 75 males[ median age 46 years, mean weight (89. 64±8. 33) kg] and 75 females[ median age 45 years, mean weight (77.23±6. 85) kg]. There were 150 persons with normal BMI in the control group, including 75 males [ ( median age 47 years, mean weight (62. 34±5.72) kg] and 75 females [ median age 45 years, mean weight (50. 16±5.06) kg]. The body height and weight of 300 persons in two groups were measured respectively and, simultaneously calculated the BMI. These data and the body composition parameters measured by the dual energy X-ray absorptiometry (DEXA) in these two groups were compared and analyzed. The data obtained used two-sample t-test analysis, bi-variable correlation used Pearson linear correlation analysis and multi-variable correlation used multiple linear regression analysis. Results FAT of arms, legs, trunk and total body of male cases in obesity group was (2.90±0.57), (7.48±1.46), ( 15.67±3.05 ), ( 30.92±5.94 ) kg respectively, FAT% was ( 30.9±5.1 ) %, ( 30.6±5.8 ) %, ( 37. 3±4.7 ) %, ( 35.1±4.4 ) % respectively, it was significantly higher than that in control group [ FAT was ( 1.12±0. 64 ), (3.27±1.22), (6. 71±3. 29 ), ( 11.61± 5. 16) kg respectively,FAT% was( 15.4±4. 8)%, ( 16. 5±5.0)%, (21.8±5.8)%, ( 18.6±5. 3)% respectively] ,P <0. 01 ;LEAN of trunk and total body of male cases in obesity group was (27.65±4. 08), (57. 09±7.08 ) kg respectively ; BMD was ( 0. 99±0. 09 ), ( 1.22±0. 09 ) g/cm2 respectively, it was significantly higher than that in control group [ LEAN was ( 22. 89±1.68 ), (48.89 s 3.72 ) kg respectively, BMD was( 0. 89±0. 07 ), ( 1.15±0. 06 ) g/em2 respectively ], P < 0. 01 ; LEAN of arms and legs of male cases in obesity group was(6.22±0.92), (17.31±2.65) kg respectively; BMD was(0.92±0. 04), (1.31±0. 09)g/cm2 respectively,and there were no statistical significance compared with those in control group [ LEAN was ( 5.99±0. 72 ), ( 16. 83±1.67 ) kg respectively, BMD was ( 0. 90±0. 08 ), ( 1.29± 0.09) g/cm2 respectively]. FAT of arms, legs, trunk and total body of females in obesity group was (3.78±1.53), ( 12. 61±3.72), ( 17. 56±2. 59), (33.71±6. 96) kg respectively, FAT% was (33.8± 4.0)%,(40. 1±6.9)%,(43.9±4.9)%, (43.5±4.2)% respectively, LEAN was(7.28±0.94), ( 14. 40 ±2. 05 ), ( 20. 71±3.08 ), ( 43.43±5.69 ) kg respectively, BMD was ( 0. 86±0. 08 ), ( 1.27± 0. 12),(0.95±0. 14), (1.19±0.09)g/cm2 respectively, they were significantly higher than those in control group [ FAT was(2. 04±0. 79), (3.79±0. 94), (6. 89±2. 56), ( 14. 68±3.57) kg respectively, FAT% was (27. 2±4. 5 ) %, ( 29. 6±3.9 ) %, ( 31.0±3.8 ) %, ( 25.9±4. 9 ) % respectively, LEAN was (5. 25±0. 63), ( 10. 65±1.44), ( 16. 65±1.50), (33. 10±3.22) kg respectively, BMD was (0. 78± 0. 04), ( 1.11±0. 09), ( 0. 82±0. 07 ), ( 1.05±0. 07 ) g/cm2 respectively ], P < 0. 01. Conclusion The significantly increasing of fat tissue in all parts of body is a major cause of change of body composition components in obesity. FAT in the trunk increases more obviously than that in other parts of the body in both males and females. The change of distribution of FAT and LEAN can obviously influence BMD.