Gallic acid (GA) is a bioactive functional ingredient widely used in pharmacology and food. For GA detection, the accuracy and selectivity can be improved from the enzyme based electrochemical sensor. However, due to the defects of natural enzymes, we introduced a dual mimetic enzyme sensor to enhance the catalytic efficiency of the electrodes and mitigate the limitations associated with the high cost of natural enzymes. The construction principle is based on the fact that the methanobactin (Mb) structure has an active center for capturing Cu(II) and the coordinated Mb(CuII) was certificated to have mimetic peroxidase (POD) and polyphenol oxidase (PPO) activities. Gold nanoparticles (AuNPs) and Mb(CuII) were modified onto the surface of the bare gold electrodes (ACE) by stepwise drop-coating. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet spectroscopy (UV), fourier infrared spectroscopy (FTIR), fluorescence spectrometer (FL) were employed to confirm the successful bonding of Mb(CuII)-AuNPs. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) verified that the addition of Mb(CuII) increased the catalytic rate of the sensor. Electrochemical tests using DPV showed that the Mb(CuII)/AuNPs/ACE sensor exhibited a high oxidation peak when GA was added. The peak potential was 0.79 ± 0.05 V. The limit of detection (LOD) was 0.27 μM (S/N = 3) for GA concentrations ranging from 1 to 1000 μM. The recoveries were determined for real samples and ranged from 96.53 to 102.54%, and high selectivity of sensor to GA was verified by anti-interference experiments. These results suggest that this work provides a new way for detecting GA.Graphical abstract: