Soil surface degradation, runoff and erosion, and transfer of nutrients from soil to runoff are the main processes controlling loss of nutrients by surface runoff in most of the agricultural areas. We studied the runoff generation effect on nutrient (N, P) transport from loamy soil under high rain intensity (60 mm h^-1). Erosion flumes were packed with <4 mm diameters aggregates and were then wetted with slow and fast wetting (with and without surface application of gypsum at 2 t ha^-1) to create different degrees of physical degradation and chemical dispersion. Slow wetting (with minimum surface degradation) or adding gypsum (minimum dispersion) significantly increased infiltration and decreased runoff and soil loss. Increasing rain intensity or wetting rate, which caused breakdown of soil surface aggregates, increased concentrations of soluble NH₃, NO₃ and PO₄ and the amount of total nutrients (TP and TN) in runoff. In contrast, gypsum amendment considerably decreased the concentration and total amount of nutrient loss in runoff. Distribution of nutrients in the soil profile depended on surface degradation (or drainage conditions). Decreasing soil surface drainable porosity by surface aggregate breakdown and/or dispersion affected the dynamics crust formation and nutrient mobilization and increased the total amount of nutrient loss by runoff and soil loss. The relationships between wetting rate, gypsum adding on nutrient loading in runoff water are discussed in this paper.