The urban construction land use scale is an important aspect of urban research, and simulating the scale and spatial layout of urban development land use is of great significance for sustainable development of urban areas. Currently, traditional methods for predicting urban land use scale lack dynamic research on the relationship between factors that affect urban land use scale, resulting in predictions that deviate from actual situations. In this paper, we combine the advantages of the system dynamics model and the FLUS model to improve traditional methods for predicting urban land use scale. Using Changsha City as a research area, we conducted a prediction of urban land use scale in 2020, and adjusted the model based on multiple years of data. The simulation results were accurate to 0.94 in terms of correlation coefficient (kappa = 0.90). We then applied this model and method to simulate urban land use scale in 2025 in Changsha City, and discussed the feasibility of using this simulation to provide reference for land development and land resource protection.