Different from the traditional measurement approach and instruments of blood glucose concentration, we propose a novel measuring method related to electrical impedance spectrum without invasion, and we have researched the correspondence between blood glucose values and impedance parameters. Considering the skin contacting impedance and cytomembrane conductivity feature, an equivalent circuit of human model was built in the MATLAB Simulink environment. We obtained the impedance parameters of the model at 1 Hz—20 MHz by simulation. The measured data were analyzed by a Cole—Cole model to derive the relationship between the impedance value and the blood glucose concentration. The results show that the electrical impedance is strong negative correlation to blood glucose concentration, as the blood glucose concentration increases, the impedance value decreases. The conclusion of this research provides a theoretical basis for non-invasive blood glucose surface-measuring.