Nanozyme can quickly and sensitively detect biomarkers to prevent the outbreak of diseases. However, the low catalytic activity and poor affinity for substrates restrict the detection performance. Montmorillonite, as a typical 2:1 layered silicate clay mineral, has a good adsorption and cation exchange ability. Thus, Fe3+ can be anchored into the layers to prepare Fe doping montmorillonite nanozyme with a peroxidase-like property, enhancing the affinity for H2O2 and realizing the colorimetric detection of H2O2. The results show that the linear range and detection limit of H2O2 are 20-500 μmol/L and 5.8 μmol/L under neutral conditions, respectively. The colorimetric method for silicate clay mineral nanozyme has a good application prospect in the fields of analytical detection and disease diagnosis.