Aims: To explore the distribution of site‐specific volumetric bone mineral density (vBMD) and analyze the mechanism of vertebral compression fractures with type 2 diabetes mellitus (T2DM) subjects using quantitative computed tomography (QCT).Materials and Methods: 304 postmenopausal women without T2DM and 274 postmenopausal women with T2DM underwent QCT scan, and all divided into three age subgroups. L1 vertebra was segmented into nine zones based on the corresponding position to the human body.Results: Whether in the T2DM or non‐T2DM of each age group, from the ventral to the dorsal side of L1 vertebra, the posterior third zones were the highest, and from the head to the foot of L1 vertebra, the middle third zones were the highest (p < 0.05). Global and most zonal vBMDs of T2DM were higher than those of non‐T2DM in the age group of 50–59 years old, vBMD‐mp of T2DM was higher in the age group of 60‐59 years old, and vBMD‐mm of T2DM was higher in the age group of 70–80 years old (p < 0.05). Zonal vBMDs in T2DM were higher than non‐T2DM and the difference decreases with age especially in the upper third of L1 vertebra and the lower third of L1 vertebra.Conclusions: Vertebral compression fractures and the confusion between T2DM and vBMD may be all caused by the heterogeneous distribution of vBMDs. The higher risk of T2DM with vertebral compression fractures may be associated with the different loss rate of global and site‐specific vBMD, independent of vBMD itself.