Purpose To evaluate the efficacy and safety of postoperative adjuvant hepatic arterial infusion chemotherapy (PA-HAIC) plus programmed death-1 (PD-1) inhibitors versus PA-HAIC alone for hepatocellular carcinoma (HCC) patients with microvascular invasion (MVI). Methods This retrospective study included HCC patients with MVI who were treated with either PA-HAIC or PA-HAIC plus PD-1 inhibitors between February 2021 and February 2024. The differences in baseline characteristics, disease-free survival (DFS), and overall survival (OS) were compared between the two groups before and after propensity score-matching (PSM). The treatment-related adverse events (TRAEs) were compared among the two groups after PSM. Cox regression analysis was utilized to determine factors affecting DFS and OS. Results A total of 102 patients were included in the study: 65 in the PA-HAIC group and 37 in the PA-HAIC plus PD-1 group. PSM analysis generated 32 matched pairs of patients in the two groups. The HCC patients in the PA-HAIC plus PD-1 group experienced significantly better DFS compared to those in the PA-HAIC group alone (HR: 0.412; P = 0.031). However, there was no significant difference in OS between the two groups (P = 0.124). Multivariate analysis identified the treatment option (PA-HAIC vs. PA-HAIC + PD-1) as an independent predictive factor for DFS of the patients. Furthermore, the results indicated no statistically significant difference in the incidence of TRAEs between the two groups (P < 0.05). Conclusion In comparison with PA-HAIC alone, PA-HAIC combined with PD-1 inhibitors could improve the DFS benefits with acceptable safety profiles in HCC patients with MVI.