In order to identify the physical, chemical and mineral compositions of loess sediments in the Yili Basin, central Asia, the authors carried out grain-size, geochemical and mineralogical analyses on collected surface soil and loess samples. Grain size measurements reveal that the loess in Yili Basin is dominated by silt and have minor sand indicating a close source. The mineral components of loess in this region are dominated by quartz, feldspar and carbonate with minor chlorite and muscovite. In contrast to the Chinese Loess Plateau, the loess in Yili Basin is rich Na2O and CaO, which indicates that loess in Yili Basin originated from a relative dry-clod and weak chemical weathering environment.