Background: Adjuvant therapy may have an important role in decreasing recurrence rates and improve survival in selected pts with HCC following surgical resection. However, there is no standard treatment options or strategies. This study aimed to investigate the safety and efficacy of donafenib combined with anti-PD-1 antibody as adjuvant therapy for HCC pts with high risks of recurrence. Methods: This prospective, open-label, single-arm study planned to enroll 30 pts who had undergone radical surgery and were diagnosed as HCC confirmed by histology or cytology with any of the following risk factors: a) Microvascular invasion (MVI); b) Satellite nodules in specimens; c) >3 tumor nodules; d) Portal vein tumor thrombosis (excluded main portal vein invasion). Donafenib combined with anti-PD-1 antibody was initiated at 4 to 8 weeks after surgical resection and continued for up to six months. The primary endpoint was the cumulative 1-year recurrence-free survival rate (RFSR). The secondary endpoints were recurrence-free survival (RFS), overall survival, and safety. Results: As of December 31st, 2022, a total of 23 pts received donafenib plus anti-PD-1 antibody (toripalimab) with a mean follow-up of 7.6 months (safety set). The most common risk factor was MVI (91%). 20 pts were included in efficacy set (three pts were excluded due to ineligibility), of whom 16 pts had one risk factor and four had two. Intrahepatic recurrence occurred in 3 pts (15%) and no extrahepatic metastasis or death was reported. The RFSR at one year was 83.0% (90%CI, 61.6%-93.1%) in all the pts from efficacy set, 81.9% (90%CI, 59.6%-92.6%) and 92.3% (90%CI, 66.0%-98.5%) in pts with MVI and MVI-low risk, and 85.1% (90%CI, 59.6%-95.1%) in pts with only one risk factor. The median RFS was not reached. The incidence of grade 3 adverse events related to donafenib and/or toripalimab was 52.2% (12/23). No pts had grade 4/5 adverse events. Adverse events leading to withdrawal of any and both treatments occurred in six (26.1%) and one (4.3%) pts, respectively. The most common grade 3 treatment-related adverse events (occurred in more than one patient) were palmar-plantar erythrodysesthesia syndrome (17.4%), rash (17.4%), alanine aminotransferase increased (13.0%), and aspartate aminotransferase increased (8.7%). Conclusions: These results were consistent with earlier reports. The combination of donafenib and toripalimab may be a promising adjuvant therapy for pts with MVI, satellite nodules or multiple tumor after hepatectomy. No safety issues were noted. Clinical trial information: NCT04418401.