Objective To explore the subdivision method of diagnosis-related group (DRG) by case-mix payment, and provide reference for reasonable imbursement mechanism and standard for DRG grouping, as well as disease cost accounting and performance assessment for hospitals. Methods The first page data of medical records of 17010 inpatients with uterine fibroids in Obstetrics and Gynecology Hospital of Fudan University from 2019 to 2021 were included. Based on the disease and treatment, combined with the length of hospital stay, other diagnosis and other factors, nonparametric test and generalized linear model were used to explore the factors affecting hospitalization expenses. Decision tree model was performed to yield case-mix related groups and predict the cost. Results The inpatients with uterine fibroids were classified into 13 groups in decision tree model based on the main surgical methods, other surgical types, and length of hospital stay. The reduction in variance was 0.34, and the coefficient of variation was 0.19-0.88. Conclusions The case-mix payment approach based on the decision tree model as the grouping method is more consistent with the actual clinical diagnosis and treatment of uterine fibroids, and can be used as method reference for the subdivision of DRG. Under the background of DRG, subdivision of DRG can provide decision-making basis for refined hospital management, including in-hospital cost accounting and performance allocation.