Forest plays a crucial role in the world carbon cycle process, and the carbon sink analysis of forest is significant for urban ecosystem management. Based on various satellite remote sensing data, forest land distribution and meteorological data, using CASA（Carnegie-Ames-Stanford Approach） model, the forest carbon sink of Changzhou City in 2022 is simulated, and its variation characteristics and mechanisms are comprehensively analyzed. The results show that the overall carbon sink of forest vegetation of Changzhou City in 2022 reached 299.4 thousand tons, with a relatively high carbon sink from April to August. The carbon sink capacity of different types of forest vegetation is different, and the arbor has the strongest ability with the highest carbon sink amount reaching 80gC/m2 in July. Meteorological factors have a related impact on forest carbon sinks with temperature having a higher impact than precipitation.