Abstract:Objective：To analyze the disease composition，age and change trend of middle-aged inpatients with malignant tumors in a certain grade A tertiary hospital from 2018 to 2022，so as to provide basis for prevention and intervention of malignant tumors in this age group. Methods：A total of 20，097 inpatients with malignant tumors aged 45 to 59 in the hospital from 2018 to 2022 were collected through the medical record management system and SQL statements，according to ICD-10 category classification，the composition of diseases was summarized，and the distribution of age and sex and the change trend of diseases were analyzed. Conclusions：The proportion of malignant tumor inpatients in the total malignant tumor inpatients between 45 and 59 years showed an increasing trend，the top three malignancies were bronchial and lung malignancies（17.41%），thyroid malignancies（10.75%）and gastric malignancies（9.33%），the total proportion of the top ten diseases reached 69.62%，and the proportion of women was higher than that of men. There were significant differences in the types of multiple malignant tumors with age. Results：From 2018 to 2022，the incidence of malignant tumors in the 45-59 age group showed an increasing trend year by year. With the rapid aging of China’s population，further improving the understanding of the characteristics of malignant tumors in this age group，and doing a good job in prevention，diagnosis and treatment are one of the important contents of the implementation of the Healthy China strategy.