Objective To clarify incidence and risk factors of hepatitis B reactivation during short term (one month) in hepatitis B virus (HBV) related hepatocellular carcinoma (HCC) patients receiving partial hepatectomy. Methods From January 2015 to December 2015, 214 consecutive patients with HBV-related HCC who underwent partial hepatectomy were retrospectively enrolled in this study. The risk factors affecting incidence of hepatitis B reactivation were analyzed. Results Hepatitis B reactivation happened in 7.0% (15/214) of patients within 1 month after partial hepatectomy. By univariate analysis, the preoperative HBV-DNA negativity and hepatitis B e antigen (HBeAg) positivity were significantly correlated with the occurrence of hepatitis B reactivation (P=0.023 and P=0.001, respectively). By multivariate analysis, the preoperative HBV-DNA negativity 〔OR=9.21, 95% CI (2.40, 35.45), P=0.001〕 and HBeAg positivity 〔OR=20.51, 95% CI (5.41, 77.73), P<0.001〕 were the independent risk factors for hepatitis B reactivation. Conclusions Hepatitis B reactivation is common after partial hepatectomy for HBV-related HCC during short term, especially in patients whose preoperative HBV-DNA negativity and HBeAg positivity. A close monitoring of HBV-DNA during short term after partial hepatectomy is necessary, once hepatitis B is reactivated, antiviral therapy should be given.