This is a prospective, open-labelled study to evaluate the efficacy and safety of sequetial transarterial chemoembolization with lipiodol and neoadjuvant chemotherapy in the treatment of initial unresectable colorectal cancer. The progression-free-survival (PFS) will be evaluated as the primary endpoints.

Inclusion Criteria:

1. Has fully understood and voluntarily signed an written Informed Consent and agreed to follow the research plan treatment and visiting plan;
2. Aged >=18 years, <= 85 years;
3. Histologically confirmed initial unresectable colorectal cancer;
4. Eastern Cooperative Oncology Group (ECOG) performance status 0-1;
5. Expected survival period ≥ 3 months;
6. At least one measurable lesion, according to RECIST 1.1;
7. The main function is normal.

Exclusion Criteria:

1. Known hypersensitivity to any of the study drugs or excipients;
2. Hypertension that is not controlled by the drug;
3. International normalized ratio (INR) > 1.5 or partially activated prothrombin time (APTT) > 1.5 × ULN;
4. WBC count < 3000 /mm^3;
5. Platlet count < 50000 /mm^3;
6. Poorly controlled diabetes before enrollment;
7. Clinically significant electrolyte abnormalities judged by researchers;
8. Patients with obvious evidence of bleeding tendency or medical history of hematochezia within 3 months before enrollment;
9. Cardiovascular diseases with significant clinical significance, including but not limited to acute myocardial infarction, severe / unstable angina pectoris or coronary artery bypass grafting within 6 months before enrollment; Congestive heart failure, New York Heart Association (NYHA) grade > 2; ventricular arrhythmia requiring drug treatment; LVEF (left ventricular ejection fraction) < 50%;
10. Active infection or serious infection that is not controlled by drug;
11. History of clinically significant hepatic disease (ALT and/or AST >5 times the upper normal limit);
12. Women who are pregnant or lactating;
13. Urinary protein ≥ ++, and the 24-hour urine protein quantification is greater than 1.0g;
14. Have any other disease, metabolic disorder, physical examination anomaly, abnormal laboratory result, or any other conditions, which according to the judgment of the investigator, it is reasonable to suspect that the patient is not suitable for the use of the study drug.