Soil water diffusivity is a significant parameter for water and salt transport in saline soil.Horizontal soil column method is used to study the relationship between soil water diffusivity and soil water content in different saline soils.The relationships among soil water diffusivity,soil water content,and Boltzmann parameter are determined.Soils with different salt contents are found to have different soil water diffusivities.Soil water diffusivity increases with increased salt content under the same condition of soil water content.Soil water diffusivity increases with increasing soil water content as well.When soil tends to be saturated,soil water diffusivity approaches infinity.The empirical relationship presented in the paper may better reflect the relationship between unsaturated soil water diffusivity and soil water content.