Abstract: Junggar basin is a representative of arid lands at northwest China. The effect of the shelterbelt system on soil characteristics is evaluated in newly-cultivated oasis of Karamay in southwest Junggar basin. The emphasis in this paper is to measure the soil physical and chemical properties and then probe the improvement effects of shelterbelt system on soil. The protection forests include Populus euphratica, Tamarix ramosissima, Populus bolleana, Lycium barbarum, Ulmus pumila, Elaeagnus angustifolia and Amorpha fruticosa. And the soil physical and chemical properties evaluation includes soil bulk density, soil nutrient content and soil solute salt. The results indicate that the shelterbelts have a notable impact on physical and chemical characteristic of soil. They could improve the soil physical structure. The construction of shelterbelts enhanced the soil fertility to a certain degree. The soil fertility in Ulmus pumila was the highest while it was the lowest in Lycium barbarum and Elaeagnus angustifolia. Total salinity content of soil in Populus euphratica obviously is reduced along with the ages of shelterbelts increased which had suppressed occurrence of the soil salification

Key words: Junggar Basin, newly-cultivated oasis, protection forests, ecological field, physical and chemical properties