This study will investigate if Toripalimab (A PD-1 Inhibitor) will improve recurrence-free survival (RFS) compared to placebo in participants with HCC and are at high risk of recurrence after complete resection with no residual of tumour.

Inclusion Criteria:

1. HCC with at least one protocol defined risk factor, diagnosed confirmed by central pathological review and received R0 resection;
2. BICR confirmed no resdual tumor lesions are detected in liver;
3. Child-Puch score, Class A;
4. ECOG score is 0;

Exclusion Criteria:

1. Patients previously received PD-1 antibody, PD-L1 antibody, PD-L2 antibody or CTLA-4 antibodies, including those who have participated in the JS001 clinical study;
2. Portal vein tumor thrombi or liver metastases or recurrent liver cancer;
3. With symptoms of central nervous system metastasis;
4. With any history of active autoimmune disease or autoimmune disease;
5. Known liver diseases with clinical significance;
6. Patients infected by hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV):

Other protocol defined inclusion/exclusion criteria could apply