Abstract: Objective To observe the preventive effect of evidence-based nursing on oral infection caused by chemotherapy in patients with acute leukemia. Methods A total of 120 acute leukemia patients with chemotherapy were selected and divided into control group and observation group, with 60 cases in each group. The control group was given routine nursing, and the observation group was given evidence-based nursing on the basis of the control group. The oral pH values on the 2^nd, 4^th, 6^th, 8^th and 10^th day after intervention and the incidence of oral infection were compared between the two groups. Results On the 8^th and 10^th day after intervention, oral pH values of the observation group were significantly higher than those of the control group(P<0.05). After intervention, the oral infection rate in the observation group was 13.33%, which was significantly lower than 30.00% in the control group(P<0.05). The oral healing time was(4.79±1.11)days in the observation group, which was significantly shorter than(10.23±2.41)days in the control group(P<0.05). Conclusion Evidence-based nursing is effective in preventing oral infection after chemotherapy in patients with acute leukemia, which can correct oral pH value, reduce oral infection rate and shorten healing time of ulcer.