Nitrogen loss on the slope with purple soil is studied by simulated rainfall of 5 rainfall intensities. The following conclusions can be drawn: (1) Proportion of surface runoff is increased wi h rainfall intensity increasing. (2) Nitrogen loss is reduced gradually with the rainfall intensity increasing. Ammonium nitrogen and nitric nitrogen are the soluble nitrogen. Their density is high in the initial time, tends to be stable or decrease with rainfall continuing, and increases in the later period. (3) Surface runoff plays a key role in nitric nitrogen loss and nitric nitrogen density plays a leading role in interflow loss. Soil nitric nit rogen loss is dominated at small rainfall intensity, but surface nitric nitrogen loss is increased with increased rainfall intensity.