PURPOSE: Investigate the bone mineral density(BMD) of college students, and analyze the characteristics of the BMD of low/normal obese college students. METHODS: The subjects of the study were 519 low/normal-weight students(18-23 years old), including 383 women and 136 men. The dual-energy X-ray test method was used to detect the percentage of body fat and BMD of college students. The BMD of obese people with low/normal weight was compared with those of non-obese people. Partial correlation analysis was used to analyze the relationship between body mass index(BMI), body fat percentage(BF%) and BMD. RESULTS: 1)Among the low-weight male college students, the whole body BMD, T-value and Z-value of the low weight obese students were lower than those of the low weight non-obese students (2.01 ± 0.22 vs 1.82 ± 0.04 g/cm2; -0.02 ± 0.15 vs -1.10 ± 0.24;-0.01 ± 0.43 vs -0.94 ± 0.64,P < 0.01);2)Among low-weight male college students, the BMD of the upper limbs, thighs, ribs, and pelvis of the low weight obese students was lower than that of the low weight non-obese students (0.68 ± 0.03 vs 0.57 ± 0.01; 1.20 ± 0.04 vs 0.96 ± 0.02;0.87 ± 0.04 vs 0.79 ± 0.06;0.78 ± 0.02 vs 0.69 ± 0.04; 0.91 ± 0.06 vs 0.77 ± 0.06 g/cm2,P < 0.01);3)Among low-weight female college students, the body BMD of the low weight obese students was lower than that of the low weight non-obese students (1.31 ± 0.29 vs 1.13 ± 0.48 g/cm2; P < 0.05);4)Among low-weight female college students, the BMD of the head, upper limbs, thighs, and trunk of the low weight obese students was lower than that of the low weight non-obese students (1.48 ± 0.57 vs 1.23 ± 0.72; 0.74 ± 0.13 vs 0.65 ± 0.20;1.07 ± 0.10 vs 1.02 ± 0.11;0.86 ± 0.07 vs 0.82 ± 0.07 g/cm2,P < 0.05); 5)In male college students, BMI was positively correlated with BMD, T-value and Z value (r = 0.694; 0.676; 0.612,P < 0.01), while BF% was negatively correlated with BMD, T-value and Z value (r = -0.523; -0.509; -0.488,P < 0.01); 6)In female college students, BMI was positively correlated with T-value and Z-value(r = 0.455; 0.261,P < 0.01), and BF% was negatively correlated with T-value and Z-value(r = -0.224; -0.225,P < 0.01). CONCLUSIONS: Low/Normal weight obese college students have poorer bone mineral density. Intervention to promote BMD in this population is of great significance for the prevention of osteoporosis.