Objective: To investigate the expression and clinical significance of miR-23a and miR-27a combined with CEA in the diagnosis of patients with colorectal cancer (CRC). Methods: The expression of miR-23a and miR-27a in GES25609 from GEO database was analyzed. From January 2014 to December 2018, 100 CRC patients who were treated in Nanjing First Hospital were collected as CRC group, and 100 healthy people who were examined in Nanjing First Hospital during the same period as normal group. The clinical characteristics, expression level of serum miR-23a and miR-27a were analyzed. To analyze the relationship between serum miR-23a and miR-27a and the clinicopathological characteristics of CRC patients, and to draw ROC curve to analyze the diagnostic value of miR-23a, miR-27a and CEA in colorectal cancer. Results: miR-23a and miR-27a in GSE25609 were significantly increased in the serum of CRC patients. The clinical samples further confirmed that the expression level of miR-23a and miR-27a in serum of CRC patients was significantly higher than that of healthy people (P < 0.05). The expression of miR-23a and miR-27a in CRC patients was closely associated with T stage, lymph node metastasis and distant metastasis. The AUC was 0.921 (95% CI: 0.879-0.962) (P < 0.001), the sensitivity was 86%, and the specificity was 94%. Conclusion: the high expression of miR-23a and miR-27a in the serum of CRC patients is closely related to the T stage, lymph node metastasis and distant metastasis of CRC patients. The combination of miR-23a, miR-27a and CEA could significantly improve the diagnosis efficiency of CRC.