The invention relates to an application of melanotropin hormone recombinant toxin in preparation drugs treating colon cancer, and belongs to medicine field. The nucleotide sequencing of the encoding gene of the melanotropin hormone recombinant toxin is expressed as SEQ ID No. 1, the melanotropin hormone recombinant toxin is capable of treating melanocortin receptor 1 as a therapeutic target, specifically capturing and killing the high expressed colon cancer cells which include colon cancer cell line HT29 and colon cancer cell line HCT-116 of the receptor. After the toxicity and pharmacodynamictests of the cell level and animal level, the specific apoptosis function of the melanotropin hormone recombinant toxin to the high expressed MC1R colon cancer cells including the human colon cancercell line HT29, colon cancer cell line HCT-116 and the like. The high expressed MC1R exist to the two cancers. The melanotropin hormone recombinant toxin has new targeting effect, is a potential therapy or add-on therapy for colorectal cancer, and has good application prospect.