Soil water erosion is a complex physicochemical process. Chemical factors play an important role in soil water erosion. The effects of soil solution concentration and composition on soil aggregation stability, surface crust formation, soil hydraulic conductivity, infiltration rate, surface runoff, and soil water erosion were systematically analyzed in the paper. The possible impacts of long-term irrigation with marginal water on soil water erosion as well as the chemical methods on reducing soil erosion also were discussed. The more attentions of effect of soil surface seal formation on soil erosion and its mechanism need to be payed to in the future research.