Abstract: Based on multi-plot-based experiments of simulated rainfall with steady in-flow rate, the erosion processes of rill on loess hillslope were simulated. Results show that: Power functions could preferably describe the rise trend of rill erosion rate with increasing runoff under different slopes and rainfall intensities,especially under different slopes. Rill erosion modulus increases with increasing slope and rainfall intensities, which could be described by exponential equation for different slopes, logarithmic equation for different rainfall intensities, and dual power equation for different slopes and rainfall intensities at the same time. Flow shear stress is the dynamic source for the development of rill erosion processes.