Correlations of soil properties and fruit size of Calligonum mongolicum Turcz. and related species were analyzed. The resullLs showed that the particle size characteristics of soils for growing Calligonum mongolicum and related species were similar, and the soils belonged to sandyones. The organic matter contents of soils were low （averaging 1.772 to 3.054 g/kg）, and the total salt content of soils was low too （averaging 0.471 g/kg）. The pH values indicated that the soils were alkaline, varying from pH 7.65 to 10.25. The results of Principal Component Analysis （PCA） and hierarchical cluster showed that 9 habitats could be divided into 6 types according to salt contents and pH values. Fruit sizes of different populations and the soil properties had significant linear correlations （P〈0.000）. It was concluded that the differences in fruit sizes among the populations of Calligonum mongolicum and related species werre related to soil variability, especially the nutrient contents of soils, and fruit size can not be considered as a taxonomic index of Calligonum mongofcum and related species.
