Objective To explore the effects of three-grade prevention and nursing when used in caring hematological malignancies (HM) patients with oral mucositis (OM).Methods Totally 128 HM patients who received chemotherapy in the Third Affiliated Hospital of Wenzhou Medical University from January 2015 to June 2016 were divided randomly into an observation group (64) and a control group (64). Patients in both groups received conventional chemotherapy nursing,and on this basis,patients in the observation group were treated with three-grade prevention and nursing,which was followed by a comparison in incidence of oral mucositis (OM), Fungous infection of lower respiratory tract (FILRT) and oral cavity fungus infection (OCFI) between patients in the two groups.Results As for OM incidence,patients in the observation group were better than those in the control group (P<0. 05). The FILRT incidence of patients in the observation was lower than that of patients in the control group (P<0.05);and the OCFI incidence of patients in the observation group were higher than that of patients in the control group (P<0. 05).Conclusions Three-grade prevention and nursing effectively reduces the incidence of OM and FILRT among HM patients during perichemotherapy,and is worthy of clinical expansion and application.