Objectives：Due to the long- term over- exploitation of groundwater and the rapid development of urbanization, a large area of land subsidence has taken place in the Suzhou—Wuxi—Changzhou area. The southern Jiangyin area is one of the most serious areas of land subsidence. In order to find out the reasons for the formation and development trend of land subsidence in southern Jiangyin area, at the same time, in order to determine the impact of building load and groundwater exploitation on land subsidence in southern Jiangyin area, combining the present situation of groundwater development and utilization urban construction planning, a three- dimensional fully coupled numerical model of building load, groundwater exploitation and land subsidence in southern Jiangyin area was established. Methods：Based on Biot's consolidation theory, a three- dimensional fully coupled mathematical model of building load, groundwater exploitation and land subsidence in southern Jiangyin area was established. At the same time, the rheological theory of cohesive soil was introduced into the mathematical model, and the constitutive relationship of soil was extended to viscoelastic—plastic, and the dynamics of soil mechanics parameters and hydraulic parameters with stress field was considered. The development trend of land subsidence in the south of Jiangyin under three conditions from December 31, 2015 to December 31, 2030 is predicted by simulation, which were building load acting alone, groundwater exploitation acting alone and superposition of building load and groundwater exploitation. Results：The simulation results show that from 2015 to 2030, building load is the main factor causing land subsidence in southern Jiangyin, and groundwater exploitation is the secondary factor. The main compression layer of land subsidence caused by building load alone is the first clay weak aquifer, and the compression amount produced by the main compression layer is 42. 94% of the total compression amount. The main compression layer of land subsidence caused by groundwater exploitation alone is the weak aquifer of the second clay, and the compression amount produced by the main compression layer is 62. 60% of the total compression amount. The land subsidence induced by the superposition of building load and groundwater exploitation has a coupling effect, and the compression produced by the superposition of the two is less than the sum of the compression caused by the single action.Conclusions: Based on Biot's consolidation theory, the three- dimensional fully coupled model of building load and groundwater mining and land subsidence in southern Jiangyin area can more accurately simulate the process of land subsidence under different conditions, and further improve the accuracy of land subsidence calculation. Three- dimensional fully coupled numerical model of building load, groundwater exploitation and land subsidence in southern Jiangyin can be used to evaluate the impact of groundwater exploitation and major engineering construction on Jiangyin City, and provide countermeasures and suggestions for the prevention and control of land subsidence in southern Jiangyin.