Background: Effective treatments are urgently needed to improve the prognosis of patients with recurrent hepatocellular carcinoma (HCC). Previous studies demonstrated that both radiofrequency ablation (RFA) and stereotactic body radiation therapy (SBRT) were promising therapies for recurrent small HCC. This trial was designed to compare the efficacy and safety of RFA versus SBRT in patients with recurrent small HCC. Methods: This is a prospective, open label, randomized controlled trial, in which patients aged between 18 and 75 years with recurrent small HCC (occurred more than 3 months after hepatectomy or RFA, a solitary HCC ≤5.0 cm in diameter without vascular invasion or extrahepatic metastasis), KPS score ≥90, Child-Pugh score ≤6, adequate organ function, and estimated life expectancy ≥6 months were considered eligible. All patients were assigned 1:1 to RFA or SBRT group, and stratification was performed according to tumor size (≤ 2.0 cm or 2.1-5.0 cm). The primary endpoint was 2-year local progression-free survival. Secondary endpoints were progression-free survival, locoregional control, overall survival, and safety. Results: A total of 170 patients were recruited during August 2019 to May 2022 (83 in RFA arm and 87 in SBRT arm). In the ITT population, median age was 56 (range, 33-75) and 15 were female. Baseline characteristics were well balanced between treatment arms. Adverse events occurred in RFA and SBRT were mainly grade 1 or grade 2 in severity, and were gastrointestinal and constitutional symptoms, or abnormal laboratory investigations. The most common adverse events were bilirubin increase（14.6%）and AST increase (13.3%) in RFA group vs ALT increase (20.0%) and AST increase (15.3%) in SBRT group. No Grade 3-4 adverse events or mortality were noted. Late adverse events were hardly observed after 3 months. The follow-up of survival data is ongoing. Conclusions: Both RFA and SBRT are tolerable and safe for patients with recurrent small HCC. This randomized controlled trial will report the survival outcomes in 2024, which will make an important contribution in clinical decision-making for recurrent small HCC. Clinical trial information: NCT04047173.