In this study, an electro-microchip was successfully used to detect the impedance signals of various Methamphetamine (MET) concentrations based on the developed competitive-immunoassay method. MET is a commonly used drug often abused by drug addicts and can cause irregular behavior; therefore, MET concentration detection is important for quantitative analysis. In this study, the gold nanoparticles (AuNPs) were introduced into an electro-microchip through the specific binding of antibodies, thus constructing a bridge between two electrodes allowing electrons to move between them. When the concentration of the anti-MET antibody-colloidal gold conjugates was diluted 100 times, the detectable limit for MET concentration was 1 ng/mL with 0.5 μg/mL of BSA-MET conjugate. Therefore, the developed electro-microchip is advantageous because it is effective with small sample volumes (30 μL), is a form of rapid quantitative measurement, and works with smaller detectable concentrations than other existing commercial detection products which have the best limit of detection of 100 ng/mL.