Finite Differential Time Domain widely used in electrical analysis and design electromagnetic field. A two dimensional modeling ZnO Nanostructure was established and approach to find a low cost glucose sensor and derived as a diabetes disease detector. Authors were interested with a PtCu as a good glucose sensor and want to find an alternative low cost glucose sensor. This letter shows that ZnO nanostructure has a linear correlation of Electromagnetic Field distribution with PtCu when given a laser with wavelength 350 - 700 nm. Electric field value decrease when EM wave given at 450 - 550 nm both of ZnO and PtCu and tend to steady at wavelength 600 nm more. In this letter we propose ZnO as a low cost glucose sensor with high sensitivity.