The therapeutic effect of transcatheter arterial chemoembolization (TACE) is limited for patients with hepatocellular carcinoma (HCC). Herein, we designed an open-label, single-arm phase II clinical trial to investigate the efficacy and safety of TACE combined with atezolizumab plus bevacizumab for patients with Barcelona Clinic Liver Cancer (BCLC) stage-B HCC. Patients will initially receive TACE. Atezolizumab and bevacizumab will be initiated 2–14 days after the first TACE session. TACE will be repeated on demand. The primary endpoint is the objective response rate. The secondary end points include overall survival, disease control rate, progression-free survival, time-to-progression and safety. The study results will provide evidence for establishing a novel therapeutic regimen for patients with unresectable HCC. Clinical Trial Registration: ChiCTR2100049829 ( ChiCTR.org ).