Abstract: Based on the Baiyangdian ecological survey in 2018 and the analysis of biological data in 2010, the models consisted of 12 functional groups covering the main paths of the ecosystem food web which includes planktonic algae, benthic algae, submerged plants, zooplankton, snails, shrimps, other benthic animals, filter-feeding fish, herbivorous fish, omnivorous fish, carnivorous fish and detritus, were established using Ecopath and Ecosim software. The structure and energy flow characteristics of the Baiyangdian ecosystem in 2010 and 2018 were analyzed and compared. The results showed that the nutritional structure in 2010 was basically consistent with that in 2018. The grazing food chain and the crumb food chain were the main energy streams in the system. The food network structure was simple and vulnerable to external disturbances in both years. Compared with the Baiyangdian ecosystem in 2010, the utilization rate of primary producers and the system energy conversion efficiency increased in 2018. The total system flow increased by 54.64%, while the total system primary production/breathing (TPP/TR) decreased from 9.56 to 1.51. It is indicated that the overall scale of the Baiyangdian ecosystem increased in 2018. The connection index (CI) and the system omnivory index (SOI) increased by 14.65% and 49.23%, and the Finn's cycle index also increased. This demonstrated that the food chain has become longer, and the influence between functional groups has increased. The system stability increased slightly and the Baiyangdian ecosystem is in the stage of ecological development and has a development trend to steady-state.