The present invention provides a method for calculating the resolution of blood glucose which corresponding with the peak value of the rising curve. The average peak value is obtained from calculating the plurality of peak value, which determined after the pre-setting sampling time. Then, the average peak value is calculated with the resistance of the measuring circuit, reference resistance, and reference voltage to obtain the resolution of the blood glucose. Furthermore, the mapping table can be fabricated by the different height of maximum peak value and outputted voltage in different presetting sampling time, such that the resolution of blood glucose can be obtained in different outputted voltage values.
