Abstract: The change of urban carbon sink is the result of the coupling of human economic and social development system and natural ecosystem in the process of rapid urbanization. The consolidation and improvement of urban carbon sink capacity is one of the important ways to achieve carbon neutrality. Evaluating urban carbon sink performance from the coupling and interaction relationship between artificial system and natural system can help accurately propose the consolidation and improvement path of carbon sink capacity. Taking Suzhou City,a high-density and rapid urbanization area,as an example,based on the InVEST model,the carbon sink among 2002，2008，2013 and 2021 under the guidance of four different economic and social development policies was measured on a spatial-temporal scale. The spatial evolution law of carbon sink was analyzed through standard deviation ellipse analysis and gravity shift,and the key factors affecting the change of carbon sink were discussed by using geographic detector. Finally,the carbon sink performance in the process of economic and social development was evaluated from the three dimensions of ecology,economy and society. The results showed that the spatial distribution of ecological carbon sinks in Suzhou presented the characteristics of "high value southern cluster,medium and low value staggered distribution". The economic and social benefits of carbon sinks continued to increase,and the policy implementation effect was obvious,but the pressure of carbon neutrality was still large. According to the results of the study,carbon sinks performance optimization countermeasures for total carbon sink improvement,quality optimization and guarantee implementation are proposed from three aspects: ecological carbon sink pattern construction,carbon sink unit delineation,decomposition index strengthening monitoring,which can provide useful reference for the optimization and improvement of carbon sink efficiency in water network areas and the realization of carbon neutrality.