• Sign Informed Consent Form (ICF) must be obtained during the screening visit, prior to the performance of any study procedure；

• Male or female patient aged ≥18 years old;

• Has histologically confirmed unresectable adenocarcinoma of the colon or rectum (all other histological types are excluded);

• RAS status must have been previously determined (mutant or wild-type) based on local assessment of tumor biopsy;

• Prior treatment regimens for the treatment of advanced colorectal cancer must have included a fluoropyrimidine, irinotecan, oxaliplatin, an anti-VEGF monoclonal antibody and/or an anti-EGFR monoclonal antibody for RAS wildtype patients;

• Has measurable or non-measurable disease as defined by RECIST version 1.1;

• Is able to swallow oral tablets;

• Estimated life expectancy ≥12 weeks;

• ECOG PS 0-1；

⁃ Has adequate organ function as defined by the following laboratory values obtained within 7 days prior to randomization:

‣ Absolute neutrophil count ≥1.5×109/L; Platelet count ≥75×109/L; Hemoglobin≥90g/L (7 days without transfusion); Creatinine clearance ≥60 mL/min, assessed using the Cockcroft \& Gault formula; Total serum bilirubin \<1.5×upper limit of normal (ULN) (unless Gilbert disease confirmed); Aspartate aminotransferase (AST; SGOT) and alanine aminotransferase (ALT; SGPT) ≤ 2.5×ULN (unless if liver function abnormalities are due to underlying liver metastasis, AST (SGOT) and ALT (SGPT) ≤ 5×ULN); Urine protein \<1+ on urinalysis or 24-hour urine protein \<1g; International Normalized Ratio (INR) or Prothrombin Time (PT) ≤1.5×ULN (For patients receiving anti-coagulant therapy the adequate therapeutic levels of PT should be confirmed).

‣ Female of childbearing potential must have been tested negative in a serum pregnancy test within 7 days prior to randomization; All patients must agree to use a highly effective method of birth control as well as their partners during the study and lasting at least 6 months after the last dose.