An EGFR immunohistochemical detection kit based on Fe<3>O4 nanoprobes and a using method thereof are disclosed. The kit includes a citric acid restoring powder agent, an endogenous peroxidase blocker, a non-specific binding site blocker, a DAB concentrate liquid, a DAB chromogenic substrate, a DAB diluting liquid, the Fe<3>O4 nanoprobes, a TBS powder agent and a hematoxylin dyeing liquor. A novel method of bonding nanometer particles and an antibody is provided to skillfully combine high peroxidase-like activity of the Fe<3>O4 nanometer particles and biological characteristics of an EGFR single-domain antibody, and a high amount of the EGFR single-domain antibody is loaded on the surfaces of the prepared Fe<3>O4 nanoprobes. The Fe<3>O4 nanoprobes are formed by the Fe<3>O4 nanometer particles surfaces of which are loaded with metal ions and the EGFR single-domain antibody the C end of which is provided with His-Tags, and has advantages of a small size, good stability, high specificity, high sensitivity and high catalytic activity. The EGFR expression level of a tumor pathological tissue can be rapidly and conveniently detected through the kit, thus providing bases for tumor treatment.