Objective To develop a risk prediction model based on the influencing factors of chemotherapy-in-duced oral mucositis in patients with hematologic tumors,and to verify the effect.Methods A case-control study was conducted to retrospectively collect the data of 444 adult patients with hematological malignancies who under-went chemotherapy in the hematology department of a tertiary hospital in Wuhan from March 2021 to January 2022.Univariate analysis,collinearity diagnosis and binary logistic regression analysis were used to explore influenc-ing factors for chemotherapy-induced oral mucositis in patients with hematologic tumors,and then a prediction mod-el which was presented with nomogram was constructed.Receiver operating characteristic,Hosmer Lemeshow and calibration charts were used to verify the predictive effect of the model,and Bootstrap resampling method was used for internal verification of the prediction model.The clinical data of 171 patients with hematologic malignancies who underwent chemotherapy in the hematology department of 2 tertiary hospitals in Wuhan from February to Oc-tober 2022 were prospectively collected for external verification.Results History of oral lesions,treatment methods,high-dose chemotherapy,vomiting,combined chemo-therapy,platelet count,and hemoglobin were independent predic-tive factors of chemotherapy-induced oral mucositis in patients with blood tumors.The area under the curve of the model was 0.822,and Hosmer-Lemeshow test P=0.602.After internal verification and external verification,the area under the curve of the model was 0.813 and 0.735,respectively.Hosmer-Lemeshow test were 0.115 and 0.820,re-spectively.These calibration charts showed that the observed results of the model were consistent with the predicted results.Conclusion The risk prediction model of chemotherapy-induced oral mucositis in hematologic tumor pa-tients has good predictive performance and extrapolation,which is an effective screening tool to help medical staff identify the high-risk patients with chemotherapy-induced oral mucositis early.