Inclusion Criteria:
1. (1) 18\~75 years old (including boundary values).
2. (2) The first diagnosis confirmed by histology or cytology is HCC.
3. (3) Barcelona Clinical Liver Cancer (BCLC) stage A-B has undergone curative resection of the tumor, with no extrahepatic metastasis or adjacent organ invasion before surgery.
4. (4) Must meet at least one of the high-risk recurrence risk criteria (as follows): Characteristics of high-risk recurrent liver cancer after surgery: preoperative single lesion\>5cm; MVI positive; Preoperative presence of sub lesions; Intraoperative margin\<1cm.
5. (5) After one month of postoperative follow-up, there was no recurrence and no systemic treatment for HCC (systemic chemotherapy, immunotherapy, targeted therapy, or other treatments for HCC) was received.
6. (6) The Child Pugh score for liver function is 5-6 points, and the liver function is grade A.
7. (7) The physical fitness status score of the Eastern Cancer Collaboration Group (ECOG) is ≤ 1.
8. (8) Research on organ function levels that meet the requirements before the first use of medication; The functional indicators of important organs meet the following requirements: serum total bilirubin ≤ 51.3 μ mol/L or 3 mg/dL; Hemoglobin ≥ 90g/L, neutrophil count ≥ 1.5 × 10/L, platelet count ≥ 100 × 10/L; aspartate or alanine aminotransferase ≤ 5 times the upper limit of normal (ULN), alkaline phosphatase ≤ 2.5 ULN, serum albumin ≥ 30g/L; Serum creatinine\<1.5 ULN; International normalized ratio (INR) ≤ 2 or prothrombin time (PT) exceeding the upper limit of the normal range ≤ 6 seconds; Serum creatinine ≤ 1.5 ULN, creatinine clearance rate ≥ 60 mL/min.
9. (9) Women who have the ability to conceive (i.e. physically capable of pregnancy) must agree to take effective contraceptive measures during the study period and within 120 days after the last dose of Trastuzumab treatment, and test negative for pregnancy within 7 days before the first dose of the study drug; Men who are capable of reproduction must agree to take effective contraceptive measures during the study period and within 120 days after the last administration of Trastuzumab.
10. (10) If the subject is infected with HBV or HCV The following conditions must be met: for inactive/asymptomatic HBV carriers, in the chronic phase; Active HBV (HBV deoxyribonucleic acid (DNA)\<500 IU/mL (or 2500 copies/mL) during screening) should be treated according to treatment guidelines. Patients receiving antiviral therapy during screening should receive treatment\>2 weeks prior to screening and continue treatment during the study period. For subjects infected with HCV: Confirmation of infection is based on detectable HCV ribonucleic acid RNA, and antiviral treatment must be completed before enrollment.
11. (11) The expected lifespan is ≥ 6 months.
12. (12) Voluntarily participate in this study and sign an informed consent form. If the subject does not have the ability to read the informed consent form (such as illiterate subjects), a witness must witness the informed process and sign the informed consent form.
Exclusion Criteria:
1. (1) The pathological diagnosis is non hepatocellular carcinoma.
2. (2) Within one month after surgery, there may be intrahepatic or extrahepatic recurrence.
3. (3) Previously received anti-tumor treatment plans such as chemotherapy, radiotherapy, radiofrequency ablation, interventional therapy, targeted therapy, and immunotherapy for liver cancer (excluding previous non tumor related surgeries and diagnostic biopsies).
4. (4) The viral load is limited to hepatitis B virus (HBV) DNA\>2500 copies/ml, hepatitis C virus (HCV) RNA\>1000, and no treatment has been received.
5. (5) Long term hormone users require long-term systemic hormone therapy (equivalent to\>10 mg prednisone/day) or any other form of immunosuppressive therapy.
6. (6) Within the first 3 months of enrollment, there has been clinically significant bleeding or bleeding tendency, or ongoing thrombolytic or anticoagulant therapy.
7. (7) Patients with complete intestinal obstruction and those with incomplete intestinal obstruction in need of treatment (but those who relieve obstruction through fistula or stent placement can be included).
8. (8) Active severe clinical infections (\>grade 2, NCI-CTCAE V5.0), including: active tuberculosis; Having a history of active tuberculosis infection for more than 1 year prior to enrollment; Has not received formal anti tuberculosis treatment or tuberculosis is still active.
9. (9) History of active immunodeficiency or autoimmune disease and/or possible recurrence of immunodeficiency or autoimmune disease in the past or long-term use of steroids.
10. (10) Uncontrolled diabetes (fasting blood glucose ≥ 10 mmol/L), severe lung disease (such as acute lung disease, pulmonary fibrosis affecting lung function, interstitial lung disease, but the recovered radiation pneumonia is excluded).
11. (11) Clinically significant cardiovascular diseases; Suffering from hypertension, antihypertensive drugs cannot effectively control (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg).
12. (12) Renal replacement therapy providers.
13. (13) Individuals who have allergic reactions to any component of the investigational drug.
14. (14) Within the past 5 years or currently suffering from other malignant tumors (excluding cured cervical carcinoma in situ, uterine carcinoma in situ, and non melanoma skin cancer).
15. (15) Pregnant or lactating female patients, and patients of childbearing age who refuse to receive contraceptive measures.
16. (16) Vulnerable groups, including individuals with mental illness, cognitive impairment, critically ill patients, etc.
17. (17) The researchers believe that patients who are not suitable to participate in this study.
