OBJECTIVE： To explore the effects of entecavir combined with chemotherapy on positive HBV in tumor patients with normal liver function. METHODS： 106 patients were selected and divided into observation group （44 cases） and control group （62 cases） according to therapy plan. Control group received routine chemotherapy according to tumor condition； observation group was given Entecavir tablets orally 0.5 mg， qd， before 1 week of chemotherapy， for consecutive 1 week. HBV reactivation rate， recurrence rate of severe hepatitis， mortality rate， serum level of ALT before and after treatment and the incidence of ADR were compared between 2 groups. RESULTS： 4 patients of observation group and 2 of control group withdrew from the study.  HBV reactivation rate， recurrence rate of severe hepatitis and mortality were 7.5％， 0， 0 in observation group and 56.7％， 50.0％， 13.3％ in control group， with statistical significance between 2 groups （P＜0.05）. Before chemotherapy， there was no statistical significance in serum levels of ALT between 2 groups （P＞0.05）； after chemotherapy， the serum levels of ALT in 2 groups were increased significantly， and the control group was significantly higher than the observation group， with statistical significance （P＜0.05）. There was no statistical significance in the incidence of ADR between 2 groups （P＞0.05）. CONCLUSIONS： Entecavir can effectively prevent HBV reactivation and decrease the recurrence rate of severe hepatitis and mortality rate in tumor patients during chemotherapy，  and doesn’t increase the risk of ADR.