This is a single arm, open-label, multi-center clinical trial to evaluate the efficacy and safety of maintenance treatment with capecitabine plus cetuximab after first-line 5-fluorouracil-based chemotherapy plus cetuximab for patients with RAS wild-type metastatic colorectal cancer.

Inclusion Criteria:

1. Subjects has been fully understand this research and volunteered to sign the consent form;
2. Histologically and/or cytologically diagnosed with RAS wild-type metastatic metastatic colorectal cancer(Phase IIIc/IV), any other histological type is excluded;
3. Subjects with stable disease or better after induction treatment with eight to twelve 2-weekly cycles of 5FU-based standard chemotherapy;
4. ECOG Performance Status (ECOG PS) ≤1(0-1);
5. Evident measurable lesion(s) that meets the Response Evaluation Criteria in Solid Tumors (RECIST 1.1);
6. Expected survival>16 weeks.

Exclusion Criteria:

1. Subjects with presence of clinically detectable second primary malignant tumors at the enrollment, or other malignant tumors within the last 5 years (excluding adequately treated skin basal cell carcinoma or carcinoma in situ of cervix);
2. Clinical refractory diseases(including uncontrolled epilepsy),and affect survivor;
3. Central Nervous System (CNS) metastatic disease or prior cerebral metastasis;
4. Researchers think that the subjects exist any clinical or laboratory abnormalities or compliance issues and not suitable to participate in this clinical study.