Guided by the idea of combining disease differentiation with syndrome differentiation in traditional Chinese medicine, this study used the form of questionnaire to summarize the changes of TCM syndromes, TCM constitution types in colorectal cancer patients before and after surgery. The Next-generation sequencing technology was used to explore the changes and differences of intestinal microorganisms before and after surgery. The correlation between changes of TCM syndromes, TCM constitution types, intestinal microbial evolution and tumor biological characteristics in colorectal cancer patients before and after surgery was analyzed. To explore the rationality of TCM in the prevention and treatment of colorectal cancer recurrence and metastasis in order to guide the individualized treatment and dietary regulation of TCM.

Inclusion Criteria:

1. Preoperative abdominal CT, colonoscopy and pathological examination were diagnosed as colorectal malignant tumor patients;
2. Having surgical indications;
3. Patients who were not treated with antibiotics or microbiological agents one week before surgery;
4. Patients who had not received radiotherapy and chemotherapy before surgery;
5. Patients or their legal representatives informed and agreed to participate in this clinical trial and signed a written informed consent;

Exclusion Criteria:

1. Have other cancer history;
2. Patients who have received invasive treatment within the past three months;
3. Inflammatory bowel disease such as ulcerative colitis or crohn's disease;
4. Combined with intestinal obstruction or intestinal perforation for emergency surgery;
5. Psychiatric history, can not join and standardize the completion of clinical investigators;
6. Pregnant or nursing women;
7. Patients treated with antibiotics or microbiological agents one week before surgery;
8. People have incomplete data;

Colorectal cancer patients admitted to the first affiliated hospital of Harbin medical university