Background: We aimed to detect IL-17, MMP-9 and CD23 in serum of patients with colorectal cancer to provide some proper references for diagnosis and treatment of this disease. Methods: Overall, 287 patients with colorectal cancer were collected in the Digestive Surgery Department of Chinese PLA General Hospital, Beijing, China from January 2017 to November 2018 and were used as the study group, meanwhile, 200 people who took physical examination in the same period were used as the control group. They were retrospectively analyzed. The concentrations of IL-17, MMP-9 and CD23 in serum were detected by ELISA 10 d before and after treatment and 30 d after treatment. The relationship between IL-17, MMP-9 and CD23 concentration and clinicopathology was analyzed. Results: The concentrations of CD23, IL-17 and MMP-9 in peripheral blood of the patients in the study group were significantly higher than those in the control group (P