Human activity has put great pressure on the sustainable utilization of fishery resources. In order to quantify human activities based on the degree of interference, a model of the marine ecological footprint was calculated in order to understand the condition of Jiangsu coastal areas from 1978 to 2014. The system dynamics approach used a dynamic nutrition model and marine ecological footprint (MEF) analysis to build a system dynamics model of the marine ecological footprint of Jiangsu coastal areas. It is feasible to verify the model by way of historical fisheries data from 2006 to 2014, simulating the ecosystem development of Jiangsu coastal waters from 2006 to 2022 under different fishing intensities. The simulation results show that from 1978 to 2014, the marine ecological footprint of Jiangsu coastal waters increased from 2.41×10⁶ hm² to 6.61×10⁶ hm², with a mean value of 5.38×10⁶ hm², which is higher than the ecological carrying capacity of 3.45×10⁶ hm², by approximately 1.5 times as much. This means that development in Jiangsu coastal waters has been at an unsustainable level according to the model simulation analysis; and assuming that the fishing intensity will only strengthen, the marine ecological footprint will fall sharply, and eventually to a zero value. The footprint drops faster and the time of tending to a zero value becomes shorter with increasing development. Based on the calculation of threshold catch, we need to reduce the fishing intensity by 50%, from now forward, to allow the fishery biomass to bounce back with smooth reductions in the ecological deficit, which might prevent a collapse in the fishery ecosystem. The research results are a worthwhile reference for making decisions on sustainable development in Jiangsu Province, and especially for forecasting ecological effects along the Jiangsu coast.