Objective A program-controlled flexible multi-point temperature measurement device was self developed for collection and analysis of skin temperature signals of diabetic patients and healthy subjects under resting and heating conditions so as to assess vasodilation function of the microcirculation, Methods With reference to the endothelial regulation spectrum of human body, wavelet analysis was performed on skin temperature signals, and the temperature fluctuation amplitudes in diabetic group and healthy control group were compared at different time periods after thermal stimulation. Results The temperature fluctuation amplitude in endothelial spectrum of diabetic group was smaller than that of healthy control group, and the decrease in skin temperature fluctuation after the power-off of thermal stimulation was remarkably smaller than that of control group, indicating that the response to thermal stimulation for diabetic patients was slower. Conclusions Vasodilation function can be quantitatively evaluated by using the fluctuation of skin temperature signals in endothelial spectrum band. Skin temperature monitoring is a potentially easy-implemented method for the health management and early diagnosis of microvascular diseases in diabetic patients.