Abstract: Clarifications of trade-offs and synergistic relationships inherent to ecosystem services in the Beijing-Tianjin sandstorm source control project area is essential for the optimization of ecosystem services and effective management of ecosystem． InVEST, RWEQ and other models are used, to quantify six ecosystem services (habitat quality, food supply, water production, carbon storage, soil conservation, wind control and sand fixation, etc.) from 2000-2020 in the Beijing-Tianjin sandstorm source control project area, to characterize their spatial and temporal patterns． The correlation coefficient method and ecosystem services trade-off degree method were used to clarify trade-offs and synergistic relationships of ecosystem services． Food supply, soil conservation, carbon storage, and wind control and sand fixation services were found to show a spatial pattern of high in the southeast and low in the northwest; from 2000 to 2020, all of these ecosystem services showed a significant increasing trend, but habitat quality as a whole decreased significantly． Two types of trade-off and synergy calculations revealed that three groups of wind control and sand fixation-food supply, water production-carbon storage, and wind control and sand fixation-water production were dominated by a synergistic relationship; habitat quality was related to wind control and sand fixation respectively． Habitat quality has a trade-off relationship with the five groups of wind control and sand fixation, soil conservation, carbon storage, water production, and food supply． Consistency analysis of the results of the two methods showed that the synergistic areas of the two groups of water production-carbon storage and wind control and sand fixation-food supply overlapped more, accounting for more than 53% of the whole region, and the areas were concentrated in the Ulanqab Plateau and Xilingol Plateau sub-regions． The trade-off areas of the habitat quality-food supply overlap more, accounting for 27.57% of the region． To maintain sustainability of regional ecosystems, future ecological construction should take into account the trade-offs and synergies between ecosystem services in different regions, and ecosystem conservation and utilization objectives．