The National Health Insurance System (NHIS) was established by the government to provide health insurance to its people. However, some obstacles will be faced by NHIS. For example, when not having proper financial management, the fiscal budget sector will experience a deficit. The issue is happening in Indonesia. The purpose of this research is to develop and evaluate problem models so it can be used for consideration in determining relevant proposed policies. This research uses NHIS data in Indonesia from 2014 to 2018. The method used is a system dynamics approach. The validation of the SD model uses the mean comparison test and t statistic. Next, the model is tested for sensitivity under extreme conditions of low, basic, and high. Patient variables generate low and high states of 34.34% and 33.24%, respectively, which affect the variable fund inventory about 49.3 trillion and -93.46 trillion, respectively. Otherwise, participant variables affect the supply of funds in low and high conditions were about -19.60 trillion and -26.19 trillion, respectively. It can be concluded variable have a direct influence on the expense variable (patient variable) gives a more dominant effect than the variable gives the overall impact (variable of expense and income) such as participant variables. Therefore, strategies related to patient variables are used as short-term strategies, while those related to participant variables are used as long-term strategies.