Abstract: Based on three aspects of ecological elasticity, supporting capacity of carrying media and pressure of carrying objects, ten influencing factors were selected, including climate conditions, hydrological conditions, ground cover, resource supply, environmental governance, social development, resource consumption, environmental pollution, population pressure and economic growth, to construct an index system of ecological carrying capacity in the Yangtze River Delta. The index system included 35 indexes. The subjective and objective weights of the evaluation factors were determined by the analytic hierarchy process (AHP) and principal component analysis (PCA). Taking Suzhou City as an example, ecological carrying capacity evaluation and obstacle factor analysis were carried out. The results showed that the overall trend of the ecological carrying capacity index of Suzhou from 2011 to 2018 was stable, and the carrying capacity level was in a medium carrying state. The subsystem of ecological elasticity had experienced the evolution process of weak stability, high stability and medium stability; the supporting capacity subsystem of carrying media had the evolution process of low support, medium support, strong support and medium support; the pressure subsystem of the bearing object showed the evolution process of lower pressure, medium pressure and higher pressure. Combined with the analysis of the obstacle factor of the ecological carrying capacity of Suzhou, it was found that the supporting capacity of bearing media was the main influencing layer of the ecological carrying capacity of Suzhou. The main obstacle factors in the factor layer included hydrological conditions, environmental treatment and environmental pollution, while the main obstacle factors in the index layer included industrial smoke and dust emission, urban regional environmental noise value and industrial wastewater emission and per capita water resources. The research results objectively reflected the status of ecological carrying capacity of Suzhou. Finally, reasonable countermeasures and suggestions were put forward for the sustainable development of Suzhou, which could provide some reference for the study of ecological carrying capacity in the Yangtze River Delta.