【Objective】 The study of the functional trait variation and environmental drivers of woody oilseed plants in different origins is of great significance for the construction of core breeding populations and the selection of improved seeds. 【Methods】 In this study, three of the largest existing natural forests of Acer truncatum in China, such as Udantara, Pine Mountain and Dai Chintara distributed around the Horqin Sandy Land, the functional traits of leaves and seeds and the soil physicochemical properties were determined, and the methods of ANOVA, correlation analysis, RDA ranking analysis and PLS-SEM model were used to study the degree of variation of functional traits and the correlation between traits and the environment in different origins in Inner Mongolia. To explore the relationship between functional traits and environmental factors of A. truncatum. 【Result】 The results showed that: (1) The differences in each functional trait of the three A. truncatum were obvious, and the coefficient of variation of each trait was as follows: specific leaf area (SLA) >oleic acid content (OA) >seed aspect ratio (ZC∶ZK> carbon-nitrogen ratio (C∶N) > nerve acid content (NA) >seed oil content (OC) >linoleic acid (LOA) >The leaf carbon content (LCC), the inter-source coefficient of variation ranged from 3.81%~19.51%, and the intra-source variation coefficient ranged from 3.60%~14.64%, and the inter-source variation was greater than the intra-source variation. (2) Among the three source areas, the content of oil and linoleic acid was the highest in the Dai Chintara area, and the highest content of nerve acid in the Udantara area. (3) The correlation results showed that there was a significant correlation between the functional traits of A. truncatum and environmental factors. (4) The RDA analysis results showed that environmental factors could explain 24.1% of the functional trait variation of A. truncatum, soil organic matter (SOM) and temperature seasonal coefficient of variation (BIO-4) were the dominant ecological factors, and meteorology and soil jointly determined the variation of A. truncatum functional traits, and meteorological factors played a leading role. (5) The PLS-SEM model showed that the path coefficient between the leaf and seed traits and the oil index of A. truncatum was small, and the synergy effect was not significant, and the average annual temperature was the main influencing factor of the oil-related indexes of A. truncatum fat, and its correlation with oil showed a negative correlation, that is, the lower temperature was conducive to the accumulation of solid oil of A. truncatum seed. 【Conclusion】 This study found that meteorology is the dominant environmental factor driving the variation of functional traits of A. truncatum, and temperature is the key factor determining the solid oil content of A. truncatum seeds, which can provide a theoretical basis for the directional cultivation of A. truncatum for oil.