Objective This study aims to explore the distribution characteristics of soil moisture profile, so as to provide theoretical support for improving the soil water environment of plantation forests and realizing the forest-water balance.

Methods With three typical plantations （Pinus tabuliformis × Picea crassifolia forest, Picea crassifolia forest, Pinus tabuliformis forest） in Nanshan Mountain of Xining City selected as research objects, one soil moisture observation point in each sample plot was set, using the tube-type soil moisture to locate and observe the soil volume moisture of the 0-100 cm soil layer from May to October in 2023, before an anlysis was conducted of the temporal dynamic change patterns of soil moisture in artificial forests.

Results Average soil water content of three typical plantation forests in descending order is P. tabuliformis × P. crassifolia forest, P. crassifolia forest, P.tabuliformis forest; the coefficient of variation of soil moisture content in descending order is P.tabuliformis forest, P. tabuliformis × P. crassifolia, P.crassifolia forest.The stable period of soil moisture, the depletion period, and the increase of moisture in the soil moisture period are classified during the observation period. The vertical change of soil moisture in artificial forests can be divided into soil moisture rapid-change layer, active soil moisture layer and stable soil moisture layer, the moisture of upper layer changes drastically, its change gradually decreases with the deepening of soil depth.

Conclusion In conclusion, the soil moisture of typical tree species in Xining City changes significantly during the growing season, and the soil moisture of P. tabuliformis and P.crassifolia is more abundant at different time stages, which can be used as tree species for local water storage and conservation.