The conversion of natural forest and cultivated land to citrus orchard has become one of the typical land use/cover change processes in major citrus producing areas in China. Enlarging citrus cultivation can bring promising profitability to smallholders. However, the ecological consequences of enlarging citrus cultivation on ecosystem services (ES) and landscape patterns remain unclear. It is of great significance to explore the ecological effects of citrus orchard scale planting on the eco-economic synergistic development of major citrus producing areas. This paper focuses on analyzing the changes of ESs and landscape pattern, their correlation and the tradeoff/synergy of ESs change caused by citrus orchard expansion, using a case of Xinfeng County, Jiangxi Province. First, we used TUPU analysis methods to characterize the spatial and temporal variation of citrus orchard expansion from 2010 to 2019, based on the data of the secondly and thirdly national land survey. Second, InVEST model was employed to evaluate critical ES dynamics caused by citrus orchard expansion, and then we analyzed its differences in different terrain gradients. Third, we applied correlation analysis to examine the tradeoffs between ESs and the relationships between ESs and landscape patterns. The results showed that:(1) from 2010 to 2019, the expansion direction of citrus orchards was mainly converted from forest land and cultivated land, and the area of citrus orchards increased from 9961.29 hm² to 12633.84 hm², with 7504.72 hm² newly transferred in and 4832.16 hm² transferred out. The contradiction among forest land, cultivated land and citrus orchard is prominent in Xinfeng County. (2) The expansion of citrus orchards has boosted the supply of citrus supply services, whereas it had a negative impact on soil conservation services and carbon storage services. Soil conservation and carbon storage services decreased by 67.19% and 35.98%, respectively, from 2010 to 2019 throughout the region as a whole. Surprisingly, its impact on water yield services was not significant, with only a 5% reduction over the research period. Moreover, citrus orchard expansion has also resulted in a decrease in landscape connectivity and a trend of fragmentation in Xinfeng County. (3) The expansion of different citrus orchards on different terrain gradients had different effects on ESs. (4) In the tradeoff and synergy analysis, there was a tradeoff relationship between supply services and support services, and there was a synergy relationship between carbon storage-water yield and carbon storage-soil conservation. It is found that landscape fragmentation is significantly correlated with ESs. These results can provide scientific evidence for the rational development and utilization of gardens and habitat protection in large-scale cash crop planting areas.