Objective To investigate the value of liver resection and radiofrequency ablation (RFA) on reactivation rates of hepatitis B virus (HBV) in hepatocellular cancer (HCC) patients with tumor ≤5 cm and determine influential factors.Methods Retrospective analysis was performed in clinical data of hepatocellular cancer patients with tumor ≤5 cm from Shengli Oilfield Centeral Hospital between July 2007 and March 2012,289 cases were assigned to liver resection group (n =157) and RFA group (n =132).Logistic regression was used to evaluate relative factors associated with HBV reactivation for univariate and multivariate analyses.The stratified x2 test was utilized to assess clinical outcomes in HBV reactivation subgroup with or without antiviral treatment.CD3 +,CD4+,CD8 +,CD4+/CD8 + and NK cell proportions were comparatively analysized.Results (1) The univariate and multivariate logistic regression analyses showed antiviral therapy,Child-Pugh grade,vascular invasion and treatment (liver resection or RFA) were significant risk factors of HBV reactivation (P ＜ 0.05).(2) HBV reactivation was lower in patients who received antiviral therapy than those who did not (10/109 vs 33/180,x2 =4.497,P ＜ 0.05).The viral reactivation rate for the liver resection group was higher than the RFA group in patients who did not receive antiviral therapy (24/98 vs 9/82,x2 =5.446,P ＜ 0.05),but the difference was not significant in patients who received antiviral therapy (6/59 vs 4/50,x2 =0.153,P ＞ 0.05).(3) The proportions of CD3 +,CD4 +,CD4 +/CD8 + and NK cell after treatment for 7 days decreased in various degrees for both the liver resection and RFA groups regardless of patients with or without antiviral therapy (P ＜ O.05).For the patients without antiviral therapy,the cell proportions in 7 days after treatment were significantly higher in the RFA group than that in the liver resection group (P ＜ 0.05),but the difference was not significant in patients with antiviral therapy (P ＞ 0.05).Conclusions For the patients with tumor ≤5 cm,the proportions of immunological cells decreased in liver resection when compared with RFA.Preoperative antiviral therapy may have partial response in immunological suppression,and lowered the incidence of HBV reactivation.