Abstract: Based on the natural distribution of Caragana microphylla Lam. in China，thirteen populations of C. microphylla Lam. collected in the East part of Inner Mongolia were evaluated by their morphological variation. Main results obtained are as follows: Results from the single factor variance analysis showed that there was a significant variation in the 13 populations studied.The principal analysis indicate that seed length, seed width and pod length were the main sources of morphological variation.Results from the regression analysis and correlation analysis showed the correlations between the morphological variation and ecological and geographic factors are significant.Based on the cluster analysis，the populations of C. microphylla Lam. investigated may be divided into three groups by morphological variation.

Key words: Caragana microphylla Lam., germplasm resources, natural population, phenotypic variation