【Objective】This study was designed to identify the surface electrochemical characteristics of Lou soil with different phosphorus levels and to study the transportation processes of phosphorus in the soil solid-liquid phase. Also, the relationship with soil surface properties was investigated and the change of surface properties of Lou soil under controlled electrolyte concentration and its internal relevance with phosphorus loss were clarified. 【Method】The number of soil particles and phosphorus loss of Lou soil under different electrolyte concentrations was obtained by rainfall simulation test. The surface chemical properties of the soil were determined by combined measurement and analysis of surface properties. Also, the surface electrochemical properties of Lou soil with different phosphorus levels and their effects on soil phosphorus loss under the condition of long-term localized application of phosphate fertilizer were studied. 【Result】The results show that: (1) The total phosphorus content of Lou soil treated with long-term application of phosphate fertilizer is 2.46 times larger than that of Lou soil treated without phosphate fertilizer. However, the former’s surface potential, surface charge density, surface electric field strength, specific surface area, and surface charge number were lower than those of Lou soil without the application of phosphorus; (2) For Lou soils with different phosphorus levels, the cumulative loss of soil particles and phosphorus tended to intensify with an increase in the surface potential (absolute value) of soil particles. There was a linear positive correlation between the cumulative loss of particulate phosphorus (PP) and the cumulative loss of soil particles; (3) The surface potential (absolute value) of Lou soil with lower phosphorus content was larger than that of Lou soil with higher phosphorus content, and the electrostatic repulsion between soil particles was larger, resulting in poor stability of soil aggregates and more cumulative loss of soil particles and their attached phosphorus; (4) Under the experimental conditions, the phosphorus loss in Lou soil was dominated by PP, accounting for 81%-99% of total phosphorus loss, and the proportion of dissolved phosphorus was extremely low. 【Conclusion】Long-term application of phosphate fertilizer can change the surface properties of Lou soil, and effectively maintain the stability of soil aggregates and attached phosphorus during rainfall. This study provides a new idea for environmental risk prevention and control of the long-term phosphorus application soil.