Inclusion Criteria:  ≥18 years old at the time of signing the informed consent; Histologically or cytologically confirmed unresectable metastatic colorectal cancer; Haven't received systematic therapy after diagnosis of metastatic colorectal cancer; Intolerable to standard treatment of oxaliplatin- or irinotecan-based intravenous combination therapy; At least one measurable lesion(s); ECOG PS 0-2; Life expectancy≥3 months; Adequate organ and bone marrow functions; Women of childbearing age must have a negative pregnancy test within the first day of the study, and contraceptive methods should be taken during the study until 6 months after the last administration; Willingness and able to comply with scheduled visits, treatment plans, laboratory tests, and other study procedure.  Exclusion Criteria:  Previous treatment with VEGFR inhibition; Participating in other drug clinical trials within 4 weeks before recruited; Have received other systemic anti-tumor therapies within 4 weeks before recruited; Non-controlled hypertension after monotherapy, that is, systolic blood pressure > 140mmHg or diastolic blood pressure > 90mmHg; Proteinuria ≥ 2+ (1.0g/24hr); Clinically significant electrolyte abnormality; Clinically significant cardiovascular diseases; Thromboembolism or arteriovenous events occurred 6 months before recruited; ≥grade 3 bleeding events 4 weeks before recruited; Evidence of CNS metastasis; Active gastric and duodenal ulcer, ulcerative colitis or uncontrolled hemorrhage in GI; Active, symptomatic interstitial lung disease causing dyspnea (≥ grade 2 dyspnea), pleural effusion or ascites; History of organ transplantation; APTT >1.5×ULN or INR>1.5; History of HIV infection or active hepatitis B / C; Allergic to fruquintinib and / or capecitabine; Pregnant or lactating women; Clinically detectable secondary primary malignancies at the time of enrollment (excluding fully treated basal cell carcinoma of the skin or carcinoma in situ of the cervix); Patients who are not suitable for the study judged by the researchers.