To investigate the correlation of age and constitution in patients with major diabetes complications, and provide the early prevention measures. Methods: A total of 166 patients were divided into 8 groups in accordance with patients’ age at which the complications occurred, and the results of constitution and distribution were statistically analyzed. Results: Diabetic nephropathy was ranked as No.1 diabetic complications (27.1%); diabetic foot the last (only 6.0%). Diabetic patients between 55 59 years old, were most likely to have diabetic complications (21.7%), while patients over 80 years old were the least likely (only 1.8%). Most patients was either Yin insufficiency constitution (n=92) or Qi insufficiency constitution (n=91), compared to 10 cases with mildly constitution. This research showed that age is correlated to constitutions (dampness heat constitution, or blood stasis constitution or Qi stagnation constitution) in patients having major diabetes complications (P<005). Conclusion: Diabetes patients with Yin insufficiency constitution or Qi insufficiency constitution are prone to diabetic nephropathy. Other three types, i.e. dampness heat, blood stasis and Qi stagnation were significantly correlated with age. These conclusions are intended to offer theoretical support and evidence based medicine for preventing diabetic complications at early stage.