There were 482 male patients with non-hyperostosis diagnosed by X-ray among 1207 males who visited West China Hospital because of pain and/or numbness in bone or/and in joints from August 2003 to December 2005; the base-line information in records included age, stature, body weight(calculated BMD, symptoms, co-morbidities, exercise frequency, and smoking. The bone mineral density of lumbar spine was determined and used to judge osteoporosis or non-osteoporosis. Comparison was made on the basic information between osteoporosis group and non-osteoporosis group by t test or chi2 test statistical analysis; the relationship of multiple factors with osteoporosis was analyzed by Logistic Regression. The results of comparison between osteoporosis group and non-osteoporosis group indicated, there were significant differences among BMI, exercise and smoking, but no significant differences were seen among age, complications of hypertension and diabetes mellitus. According to the results of multiple regression analysis, BMI and smoking are the risk factors of osteoporosis, yet exercise is the protection factors of osteoporosis; the risk of osteoporosis increases by 0.654 times in men with BMI scaling up by 1 kg/m2 (P = 0.004). Therefore, we conclude that BMI is a risk factor of osteoporosis in male, and it may be related to body fat distribution.