Inclusion Criteria:

          1. Males or females, Aged ≥18 years and ≤75 years

          2. Diagnosis of histologically confirmed adenocarcinoma of the colon or rectum

          3. First occurrence of metastatic disease(not curatively resected)

          4. RAS/BRAF wild-type status in tumor tissue

          5. At least one measurable lesion by computer tomography(CT) or magnetic resonance
             imaging (MRI)according to RECIST1.1 criteria (not in an irradiated area)

          6. Eastern Cooperative Oncology Group(ECOG)performance status of 0 or 1 at trial entry

          7. Life expectancy of at least 3 months

          8. Medically accepted effective contraception if procreative potential exists(applicable
             for both male and female subjects until at least 90 days after the last dose of trial
             treatment)

          9. Recovery from relevant toxicity due to previous treatment before trial entry

         10. Signed the informed consent form voluntarily

        Exclusion Criteria:

          1. Radiotherapy or surgery（excluding prior diagnostic biopsy）in the 30 days before trial
             treatment

          2. Hepatic, marrow, liver and renal function as follows:

             Marrow: white blood cell count <3.0 × 109/L with neutrophils<1.5 × 109/L, platelet
             count<100×109/L and hemoglobin<90 g/L; Liver function: Total bilirubin >1.5 × upper
             limit of reference range; Aspartate transaminase (AST) and alanine transaminase (ALT)
             > 2.5 × upper limit of reference range , or> 5 × upper reference range in subjects
             with liver metastasis; Renal function: Serum creatinine >1.5 × upper limit of
             reference range, or creatinine clearance<50 mL/min

          3. Previous chemotherapy for CRC adjuvant treatment if terminated <12 months before
             diagnosis of recurrence or metastatic disease

          4. Previous treatment with anti-EGFR monoclonal antibody, epidermal growth factor
             receptor tyrosine kinase inhibitor, or other EGFR targeted inhibitors(such as
             cetuximab, Nimotuzumab, or panitumumab)

          5. Known hypersensitivity or allergic reactions against any of the components of the
             trial treatments

          6. History of organ allograft, autologous stem cell transplantation, or allogeneic stem
             cell transplantation

          7. Other non-permitted concomitant anti-cancer therapies

          8. Known brain metastasis and/or leptomeningeal disease

          9. Previous malignancy other than CRC in the last 5 years except basal cell cancer of the
             skin or preinvasive cancer of the cervix

         10. Participation in another clinical trial within the past 30 days

         11. Concurrent chronic systemic immune therapy or hormone therapy except physiologic
             replacement

         12. Any unstable systemic disease, such as active infection, uncontrolled hypertension,
             unstable angina pectoris, angina in the last 3 months, cardiac failure of New York
             Heart Association classes ≥II, history of myocardial infarction, serious cardiac
             arrhythmias that require drug treatment, liver, kidney or metabolic disease in the
             last 6 months

         13. Acute or sub-acute intestinal occlusion or history of inflammatory bowel disease

         14. severe bone marrow function failure

         15. Any disease, metabolic disorders, or physical/laboratory examination suspected, or
             patients with high risk of complications

         16. Known and declared history of human immunodeficiency virus(HIV)infection

         17. HBV-DNA >1.0 × 103copy

         18. Pregnancy or breastfeeding

         19. Alcohol or drug abuse

         20. Legal incapacity or limited legal capacity