[Objective] The effects of abandoned farmland, planting spring-sown crops and mixed sowing of legume and herbal grass on soil salinity were analyzed in order to provide scientific support for the prevention and control of soil salinization by using biological measures in irrigated areas along the Yellow River in Gansu Province.[Methods] Bare land (CK), Triticum aestivum and mixed grass (Elymus nutans×Medicago sativa) were employed to conduct treatments. Indicators related to vegetation and micro-environment and topsoil (0-5 cm) moisture and salinity were measured to analyze the relationship between vegetation characteristic index and salt content.[Results] The salinity of topsoil in bare land showed a W-shaped curve pattern throughout the year, with three peaks occurring in early spring, late summer and late autumn. The salinity in wheat land showed a U-shaped trend with the peak in early spring and late autumn. The salinity in mixed grass land was only higher in the early spring. By the end of autumn (October), the salinity of topsoil in wheat field was 18.4% higher than that in bare land, while in grassland, was 55.9% lower than that in bare land. Compared with that in the March of two consecutive years, soil salinity in bare and wheat fields increased by 23.7% and 14.8% respectively, while in pasture field, decreased by 28.2%. There were extremely significant negative correlation between vegetation characteristics and salinity (p<0.01), among them, the negative correlation between vegetation coverage and salinity was the strongest (up to -0.916). With the increase of vegetation coverage, height, and biomass by 1%, 1 cm and 1 g/m², the soil salinity would reduced by 0.031, 0.139 and 0.014 g/kg.[Conclusion] Abandoned farmland and short growing period of spring-sown crops are easy to cause salt accumulation of topsoil and soil secondary salinization in irrigated areas along the Yellow River in Gansu Province, while mixed planting legume and grass with long growth period can effectively reduce topsoil salinity and prevent soil salinization.