Inclusion Criteria:  Advanced HCC (BCLC stage C or CNLC IIIa/IIIb ) with diagnosis confirmed by histology/cytology or clinically Patients who have Tumor recurrence after surgical resection or ablation are allowed to be included Patients who previously received local treatment, such as transcatheter arterial chemoembolization, transcatheter arterial embolization and radiotherapy, are allowed to be included At least one measurable lesion Child-Pugh score ≤7 Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Adequate organ and hematologic function Life expectancy of at least 3 months  Exclusion Criteria:  Diffuse HCC Macrovascular invasion involving the main trunk or inferior vena cava Central nervous system metastasis History of malignancy other than HCC Esophageal and/or gastric varices bleeding within 3 months prior to initiation of study treatment Uncontrolled ascites History of hepatic encephalopathy Patients who received prior systemic therapy (chemotherapy, targeted therapy or immunotherapy) or hepatic arterial infusion chemotherapy (HAIC) for HCC History of organ and cell transplantation Active severe infection; use of antibiotics within 2 weeks prior to injection of sintilimab Autoimmune disease or immune deficiency Severe organ (heart, kidney) dysfunction