Colorectal cancer is one of the most common malignant tumors worldwide. At present, the molecular mechanism of colorectal cancer is still under continuous exploration. In order to determine the carcinogenic effect and progress of related candidate genes in colorectal cancer. Three data sets were selected from the gene expression database (GEO) [GSE21510 (148 samples), GSE32323 (44 samples), GSE15781 (42 samples)], and analyzed the expression of differential genes and functional enrichment. By establishing a protein interaction network, using STRING and Cytoscape to analyze molecules. A total of 472 differential genes were selected, including 212 up-regulated genes and 260 down-regulated genes. The rich functions of differential genes and their pathways mainly include regulation of cell proliferation, cell activity, ion transmission, decomposition of lipids, multicellular organisms, cytokine biosynthesis, monosaccharide metabolism, recognition of receptor signaling pathways, and carbonate dehydration enzyme activity, sodium reabsorption, peroxisome proliferator activated-receptor signaling pathway, and starch and sucrose metabolism. During the process of identifying and analyzing 15 core genes, it was found that these genes were mainly enriched in receptor protein signaling pathway, cell surface receptor signal transduction, and cytokine activity, growth factor activity, and chemokine signaling pathway. Survival analysis showed that AGT, CXCL2 may be involved in carcinogenesis, promote cancer metastasis, and affect prognosis. Through the screening and identification of 472 differential genes and 15 core genes, the tumor suppressor gene AGT and the tumor-promoting gene CXCL2 may be regarded as biomarkers of colorectal cancer, providing new information for the diagnosis, treatment and research of colorectal cancer molecular target.