Objective: Taking the team of practicing (assistant) physicians as the research object, it aims to construct a system dynamics prediction model for the demand system of practicing (assistant) physicians in China, in order to predict the demand quantity of practicing (assistant) physicians in China from 2023 to 2035, and then propose policy recommendations to promote the rational allocation of practicing physicians. Methods: By summarizing the research results in relevant fields and the influencing factors of the demand quantity for practicing (assistant) physicians, a causal relationship diagram and a flow chart are drawn, and a dynamic feedback structure of the model is established. MATLAB Software is used to select the GM (1,1) grey model method, spline interpolation method, curve fitting method, and moving average prediction method to estimate the parameters of the key demand factors in the model. Result: Literature analysis found that the influencing factors of the number of practicing (assistant) physicians mainly include economic, social, demographic, and institutional factors. The system dynamics model constructed includes 1 stock, 2 flows, and 21 auxiliary variables. The historical test results of the stock of practicing (assistant) physicians show that this indicator’s average absolute percentage error from 2011 to 2020 was 1.911%. From 2023 to 2035, the stock of practicing (assistant) physicians in China will increase from 4.40025 million to 5.63073 million, and the number of practicing (assistant) physicians per thousand population will increase from 3.08 to 4.02. The demand for practicing (assistant) physicians will increase from 4.815 32 million to 4.691 09 million, and the demand for practicing (assistant) physicians per thousand population will increase from 3.22 to 4.64. Conclusion: Building a system dynamics model based on historical data and other research prediction parameters for predicting physician demand has high accuracy and stable prediction results, and can serve as a long-term model to provide a basis for formulating health manpower development plans.