Objective To study the protective effects of pre-storing glycogen on warm ischemia reperfusion injury during partial hepatectomy. Methods Thirty-eight patients were randomly divided into a trial group (n=19) and a control group (n=19). In the trial group, patients were given high concentration glucose intravenously during the 24 hours before the operation. The hepatic lesion was resected after portal triad clamping in the two groups. Liver function of all patients was measured before the operation and the first and fifth days after the operation. Normal hepatic tissue was biopsied to measured hepatic tissue glycogen contents before the operation and the change of superoxide dismutase (SOD) at the point of pre-ischemia, post-ischemia, and reperfusion 2 hour. Bcl-2 mRNA, a well known anti-apoptotic factor, was also detected using quantitative polymerase chain reaction. Results The hepatic tissue glycogen content of the trial group was significantly higher than that of the control group before the operation (Plt;0.01). Liver function of the trial group was significantly better than that of the control group on the first and fifth day after operation (Plt;0.05). There was significant difference in SOD activity between the two groups at the end of hepatic vascular occlusion and at the point of 2-hour reperfusion (Plt;0.05). Furthermore Bcl-2 mRNA expression of the trial group was notably up-regulated at the point of 2-hour reperfusion compared to the control group. Conclusion Pre-store storing glycogen might protect liver ischemia reperfusion injury caused by hepatic vascular occlusion during partial hepatectomy. The potential mechanism might be that pre-storing glycogen enhances Bcl-2 expression.