Abstract: Principal component analysis (PCA) and correlation analysis (CA) were applied to analyze the correlation of the main chemical components in Astragalus membranaceus var. mongholicus and ecological factors. The results showed that the contents of astragaloside, campanulin, ononin, kaempferol and astragalus polysaccharides (APS) of A. membranaceus var. mongholicus produced in Shanxi were significantly higher than in Inner Mongolia and Gansu. The main climatic factors for affecting the contents of chemical ingredients in A. membranaceus var. mongholicus were annual average relative humidity, sunshine hours and average July temperature. Calcium was the main factor in the soil affecting the chemical ingredient contents, and calcium was negatively correlated with the contents of calycosin glycosides, kaempferol, ononin, quercetin and APS in A. membranaceus var. mongholicus within a certain range.