The invention discloses a non-toxic photoelectrochemistry competition immunoassay method of zearalenone based on a peptide sensor. According to a sensing interface building method, carbon nanohorns, cysteamine functional golden cone and polyglycine are used as substrates; corn zeranol antibodies (Ab) are further immobilized; tyramine functionalized nanometer rutile type TiO2 mesoscopic crystals are used for immobilizing peptide chains with the specific sequences as a photoelectric probe; the peptide chain has the effect of simulating the zearalenone, the zearalenone can compete with the markedphotoelectric probe to combine the corn zeranol antibodies immobilized on the sensing interface. The photoelectric probe combined onto the sensing interface can further combine with tyramine-Rutile TiO2 mesoscopic crystal compounds under the catalysis effect of horseradish peroxidase; optoelectronic signals can be further amplified. On the basis, the non-toxic photoelectrochemistry competition immunoassay method on the corn zeranol can be built.