Abstract:Objective:To explore the major factors influencing the medical expenditure of patients with lung cancer by the pathway analysis method.Methods: Descriptive statistics and the pathway analysis method was applied to inquiry the? factors?affecting hospitalization?costs?of?inpatients with primary diagnosis of lung cancer at a tertiary hospitals in Anhui province. Results:The average medical cost of 25 817 patients with lung cancer was 18 816.91 yuan with a median of 12 197.20 yuan,and the average length of hospital stay was 10.19 days with a median of 8 days. The length of hospital stay was the?foremost factor affecting hospitalization cost of inpatients with lung cancer directly,source of patients,surgical operation?situation, patients' age,the year of medical treatment,condition at admission and discharge had not only the direct effects but also indirect effects on the medical cost,the length of hospital stay,the expense payment forms only influenced the hospitalization cost directly,however,gender only had the indirect effects.Conclusion:The length of hospital stay is the main factor affecting the medical expense of patients with lung cancer,comprehensive steps should be taken,aiming to alleviate the economic burden of patients.