Patients with advanced-stage or intermediate-stage hepatocellular carcinoma (HCC) unsuitable for transarterial chemoembolization (TACE) had poor prognoses. Recent advancements in hepatic arterial infusion chemotherapy (HAIC) and immune checkpoint inhibitors (ICIs) have demonstrated higher tumor response rates, which improved overall survival (OS). HAIC achieves an OS rate of approximately 14.5-15.3 months with a 39.1-42.5% tumor response rate. In comparison, ICIs have a 12-14 month OS rate with a 26-33% tumor response rate. Given these promising responses, this study evaluates the efficacy of conversion therapy with curative intent following HAIC or ICIs, focusing on survival outcomes. We retrospectively analyzed 80 patients with advanced or TACE-unsuitable intermediate HCC. Patients completed two HAIC or four ICI cycles, followed by Response Evaluation Criteria in Solid Tumors (RECIST) criteria imaging. Based on demographics, cirrhosis status, Barcelona Clinic Liver Cancer classification (BCLC) stage, treatment responses, and treatment modality, survival impacts were analyzed. OS was compared between HAIC and immunotherapy groups. The effect of conversion therapy with curative intent on survival outcomes was analyzed using a Cox regression model. Among the 80 patients, 26 achieved positive response (CR/PR) with HAIC or ICIs, and 9 of them subsequently underwent conversion therapy with curative intent. Key prognostic factors included Child-Pugh stage B vs. A (HR=2.21, p=0.041), BCLC stage C vs. B (HR=4.38, p=0.011), and elevated AFP levels (HR=5.02, p<0.001). Positive responders saw substantial survival benefits (HR=0.26, p=0.001). Patients undergoing conversion therapy exhibited significantly enhanced survival. Median OS was 13.58 months with standard therapy, while the curative intent surgery group did not reach the median OS (p=0.002). For CR/PR patients, 48-month survival was 75.0% for the curative surgery group versus 38.0% for standard treatment. Conversion therapy with curative intent following HAIC or ICIs might enhances survival in patients with advanced or TACE-unsuitable intermediate-stage HCC.