Objective: The paper attempts to explore the factors influencing the selection of primary medical institutions for the first diagnosis of the middle-aged and elderly people within two weeks of illness and injury, so as to provide the reference for optimizing the selection of primary medical institutions for the first diagnosis. Methods: Multi-stage stratified cluster random sampling method was used to select middle-aged and elderly persons aged ≥45 years from 9 cities in Henan Province for the questionnaire survey. SPSS 24.0 was used for descriptive analysis, single factor analysis and binary logistic regression analysis. Results: 77.47% of the middle-aged and elderly go to medical institutions at the grassroots level for the first diagnosis. Regression analysis results show that basic medical insurance for employees, health records, anxiety or depression, self-reported health, alcohol drinking and chronic diseases affect the middle-aged and the elderly to choose first diagnosis at the grass-roots level within two weeks of illness and injury. Conclusion: Primary medical institutions should give full play to the advantages of medical insurance, improve and optimize health records, pay attention to the physical and mental health of middle-aged and elderly people, and take targeted measures to improve the diagnosis and treatment of chronic diseases, strengthen publicity and education of health management. increase publicity on hierarchical diagnosis and treatment and guide middle-aged and elderly people to choose community-level medical institutions within two weeks of illness and injury.