In this study, magnetic metal organic framework (MOF) particles were prepared using in situ grown iron-based MOF with Fe₃O₄ as the core, and then a magnetic nanozyme was prepared by doping the surface of the MOF particles with Pt nanoparticles, whose surface was subsequently modified with histamine aptamer H1 to obtain a colorimetric probe. After the probe was combined with different concentrations of histamine, the aptamer was conformationally changed, causing differences in the color reaction from H₂O₂-mediated tetramethylbenzidine (TMB) oxidation catalyzed by the nanozyme and thereby enabling one-step colorimetric detection of histamine in fish. The results showed that the linear detection range of the developed sensor was 0.1–70 μmol/L, the detection limit was 0.943 μmol/L, and the recoveries for spiked mackerel samples were 90.7%-100.5%. This method has a wide linear detection range, high sensitivity and strong specificity, and can be used for the rapid detection of histamine in fish and other complex food samples.