Objective To explore the matching relationship between the supply and demand of different types of integrated elderly care and medical service for the elderly population in the region, and achieve the simulation purpose of coordinated allocation and balanced development of supply and demand of integrated elderly care and medical service. Methods Combining literature, interviews, and expert consultation to sort out the main factors and system element relationships between the supply and demand of integrated elderly care and medical service in the region, the Vensim software was used to clarify the relationships and operation mechanisms between the subsystems of supply and demand of integrated elderly care and medical service. The data of the construction base for the integrated elderly care and medical service project in Suzhou city, Jiangsu province from January 1, 2010 to December 31, 2022 were selected. Results Combined with the accessibility and completeness of data, the main variables and indicators of the five subsystems were screened, and the causality diagram and flow diagram of the system dynamics were drawn to clarify the main variables and flow direction of the subsystems, and the constructed model was more stable in simulation operation. The simulation model results showed that the supply-demand ratio of home-based elderly care and community elderly care decreased relatively before 2012, and the institutional elderly care model gradually emerged and developed from 2013 to 2018. From 2019 to 2022, the supply-demand ratio of medical care with elderly care and elderly care with medical care decreased. Conclusions Based on the theoretical foundation of system dynamics, the supply and demand the integrated elderly care and medical service in the region are regarded as a complex system. Through the analysis of the system elements among the subsystems and the sorting out of the mechanisms, it can provide certain theoretical support for constructing and improving the system dynamics model for matching the supply and demand of integrated elderly care and medical service in the region.