Objective　To investigate the occurrence of postural hypotension (PH) in patients suffering from type 2 diabetes mellitus with or without hypertension (DMH or DM), and the relationship of PH and diabetic neuropathy, hyperinsulinemia and insulin resistance. Methods　A total of 30 cases of type 2 DM and 30 cases of DMH were included in this study. The blood pressure of all subjects were measured in supine and standing body positions respectively and PH was defined as a decline from supine to standing was ≥20 mmHg in systolic blood pressures (SBP). The concentrations of blood glucose and plasma insulin were measured to calculate the insulin sensitive index (ISI). Autonomic and peripheral function was determined by measuring the postural heart rates and the conduction speeds of superficial peroneal and communicating branch of peroneal nerves etc respectively. Results　Significant difference (P<0.01) was found in the occurrence of PH in the patients with DM (40%) and those with DMH (67%). The changes of postural blood pressure were more obvious in those with DM+PH and DMH+PH than in those with simple DM (P<0.01). The conduction speeds of newes were significantly lower in those with DMH+PH than with simple DM (P<0.05), but the occurrence of autonomic neuropathy had no difference between the 2 groups. There was no difference in postural heart rate, body mass index and blood glucose levels in fasting and 2 h after meal among the DM, DM+PH and DMH+PH groups. The concentrations of plasma insulin of those with DMH+PH were significantly higher, but their ISI significantly lower than those of the patients with DM respectively (P<0.01). The decline of postural SBP in patients with DMH+PH had a significantly positive correlation with their plasma insulin levels in fasting condition (r=0.689, P<0.01). Conclusion　The patients with DMH are more prone to PH compared with those only with DM and PH damages their peripheral nerves. Most of diabetic patients with PH suffer from obvious IR and hyperinsulinemia, and if with hypertension, the above metabolic disturbances are more severe.