In order to solve the problem of many user requirements in the design of accompanying children's infusion seats, the work aims to introduce an integrated FKM-SEM theoretical method to the process of requirement analysis to identify the core design requirements, improve the targeting of design analysis, and then design user-satisfying accompanying children's infusion seats to optimize the experience of medical treatment. Under the framework of FKM-SEM integrated theory and methodology, 22 user requirements were identified by firstly collecting, integrating and refining user requirements through field observation and user interviews, and then user requirements were classified into categories with the help of fuzzy Kano model, producing 7 essential requirements, 5 expected requirements, 4 attractive requirements and 6 undifferentiated requirements. Next, the structural equation model was constructed to analyze the influence mechanism between the requirements and user satisfaction, and clarify the degree of influence of each user requirement on user satisfaction. Finally, based on the results of the structural equation model, the selection of many user requirements was completed, and 12 core user requirements were identified to guide the design. Based on the integrated theoretical method of FKM-SEM, the innovative design of accompanying children's infusion seats is completed, which shows that the method applied to the design and analysis of children's infusion seats has a certain degree of operability and practicability, and can effectively solve the problem of difficulty in making a choice in the face of the user's diversified and ambiguous needs in the process of design, thus helping the designer to control the focus of the design and improve the design efficiency.