Objective: The paper attempts to analyze the composition and influencing factors of inpatient costs of gallstones patients paid by DRG, and provide a basis for hospitals to reasonably control costs to reduce deficits. Methods: Using the data of gallstone inpatients cost included in DRG payment in a tertiary hospital in Panzhihua City of Sichuan Province from 2019 to 2021 as a sample, we used univariate analysis for the cost comparison and established a BP neural network model to analyze the main influencing factors of patients' inpatient costs. Results: Drug and material costs were the items that accounted for the highest percentage, with a combined percentage of 44.59%. The factors influencing the inpatient costs of gallstones patients were, in descending order of importance, the number of days of hospitalization (0.373), whether surgery was performed (0.212) and age (0.089). Conclusions: BP neural network model can be applied to analyze the influencing factors of hospitalization expenses and hospitals can reasonably control expenses, improve the refined management by the model, which is valuable in practice.