Objective To investigate osteoporosis and its main associated factors in patients with type 2 diabetes (DM). Methods Bone mineral density(BMD)of lumbar vertebrae 2～4 and proximal femur in 40 type 2 diabetic patients were measured with dual energy X-ray absorptiometry and compared with control group(30～35 years old). Serum Ca, P, ALP and connective peptide in type 2 diabetes mellitus patients were measured. Results The area under the connective peptide releasing curre in osteoporosis group was lower than that of non-osteoporosis in type 2 diabetes. Conclu.sion BMD is correlated with the pancreatic islet function. The patients with pancreatic islet failure develop osteoporosis easily.