There is an apparently variation of soil moisture and salinity in the Yellow River Delta. In order to explore the characteristics and influencing factors of the variation to restore the ecology of local Tamarix community, the two natural Tamarix forests, poorly-developed (N₁) and well-developed (N₂) states were selected, the groundwater table depths and salinity, soil moistures and salinity, salt enrichment ratios and Cl^-and Na⁺ contents at the two sites were compared and analyzed. The results show that the salinity of groundwater at N₂ site is higher than N₁site, and its average groundwater table is lower than N₁site. Soil moisture is higher at N₂ site than N₁ site in rainy season but lower at N₂ site than N₁ site in dry season, especially in the inner region (distance from the plant is 0-30 cm). Soil salinity is decreased with soil depth at the two sites, and “salt valley” and “salt island” is appeared in rainy and dry seasons, respectively. “Salt valley” at N₂ site is stronger than N₁ site. During the rainy season, the contents of Cl^- and Na⁺ in the inner region is generally lower than those in the outer region (distance from the plant is 30-90 cm) with the “left-right” spatial distribution at N₂site.Whereas, the “up-down” spatial distribution is appeared at N₁ site, which further illustrated that “salt valley” effect is more obvious at N₂site in the rainy season. In conclusion, “salt valley” and “salt island” effects are the crucial strategy for Tamarix Chinensis adapting to heavily saline habitat. Therefore, it is an effective way to apply suitable planting regime for tamarisk, to promote the growth of canopy for enhancing “salt valley and island” effects, which are beneficial to the stability of tamarisk community and the restoration of saline-alkali soil.