Inclusion Criteria:
* 1.18 years old ≤ age ≤ 75 years old, male or female;
* 2\. ECOG score 0\~2 points;
* 3\. Patients with locally advanced gastric cancer and colorectal cancer after radical surgery (R0 resection);
* 4\. Gastric cancer: patients with stage III (pT1N3bM0, pT2N3M0, pT3N2-3M0, pT4aN1-3M0, pT4bN0-3M0);
* 5\. Colorectal cancer: patients with stage III (T any N+M0);
* 6\. Normal function of main organs
* 7\. Female subjects of childbearing age must carry out a serum pregnancy test within 3 days before starting the study medication, and the result is negative, and are willing to use a medically approved effective contraceptive measure (such as intrauterine device, contraceptive or condom) during the study period and within 3 months after the last administration of the study medication; For male subjects whose partners are women of childbearing age, they should undergo surgical sterilization or agree to use effective methods of contraception during the study and within 3 months after the last study administration.
* 8\. Subjects voluntarily joined the study and signed the informed consent form, with good compliance and cooperation in follow-up.
Exclusion Criteria:
* 1\. Postoperative distal metastasis or failure to achieve R0 resection;
* 2\. Have experienced any anti-tumor treatment before surgery, including chemotherapy, radiotherapy and targeted drug treatment;
* 3\. Patients with contraindications to chemotherapy;
* 4\. Other malignant tumors in the past 3 years;
* 5\. Clinically obvious bleeding symptoms or obvious bleeding tendency (such as gastrointestinal bleeding, gastric ulcer bleeding, gastrointestinal bleeding, hemorrhagic gastric ulcer, stool occult blood++or above the baseline, or vasculitis);
* 6\. Uncontrolled hypertension (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, despite the best drug treatment);
* 7\. People newly diagnosed with angina pectoris within 3 months before screening or suffering from serious cardiovascular diseases within 6 months before screening, including unstable angina pectoris or myocardial infarction; Arrhythmias (including QTcF: male ≥ 450 ms, female ≥ 470 ms) require long-term use of antiarrhythmic drugs; ≥ Grade 2 congestive heart failure (NYHA classification);
* 8\. Severe infection (such as the need for intravenous drip of antibiotics, antifungal or antiviral drugs) occurred within 4 weeks before the first administration, or fever of unknown cause occurred during screening/before the first administration\>38.5 ° C;
* 9\. Known history of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation;
* 10\. Pregnant or lactating women; Those with fertility who are unwilling or unable to take effective contraceptive measures;
* 11\. It is known that it will produce allergy, hypersensitivity or intolerance to the test drug and its excipients;
* 12\. Subjects who are participating in other clinical studies or whose first medication is less than 4 weeks from the end of the previous clinical study (the last medication), or who have 5 half-lives of the study drug;
* 13\. Subjects are known to have a history of abuse of psychotropic substances, alcohol or drug abuse;
* 14\. The researcher believes that there are any conditions that may harm the subject or cause the subject to fail to meet or perform the research requirements.
