Objective:To retrospectively analyze the impact of adjuvant iodine-125( 125I)brachytherapy on postoperative recurrence and survival for patients with hepatocellular carcinoma (HCC) treated with partial hepatectomy with narrow resection margins. Methods:The data of 72 HCC patients who underwent partial hepatectomy with narrow resection margins from January 2011 to June 2015 at Weihai Municipal Hospital were analyzed retrospectively. The patients were divided into the adjuvant 125I brachytherapy group ( 125I group) ( n=36) and the control group ( n=36). The data of the two groups of patients were compared to study the factors influencing long-term survival outcomes and recurrence. Results:The follow-up time was (45.0±18.4) months. There were no deaths relating to 125I brachytherapy. The median recurrent free survival (RFS) was significantly longer in the 125I group than the control group (41.0 months vs 21.5 months, P<0.05). The 1-, 3- and 5-year RFS rates of the 125I group and the control group were 94.4%, 58.3%, 41.6% versus 86.1%, 33.3%, 25.0%, respectively ( P<0.05). The 1-, 3- and 5-year overall survival (OS) rates of the 125I group versus the control group were 97.2%, 69.4%, 52.8% versus 94.4%, 52.8%, 27.8%, respectively ( P<0.05). On multivariate analysis, 125I implantation was an independent factor affecting RFS and OS ( HR=2.112, 95% CI: 1.155-3.860, P<0.05; HR=2.492, 95% CI: 1.272-4.693, P<0.05). Conclusion:Adjuvant 125I brachytherapy was safe and effective for HCC patients with narrow resection margins after hepatectomy. It obviously reduced the tumor recurrence rate and prolonged the long-term RFS and OS.