To reveal the mechanisms of soil erosion by sheet flow is important for the understanding of erosion processes on loess slope. With artificially simulated rainfall tests

sheet flow erosion processes on loess hill slope are studied and the follow ing results are obtained: ( 1) Under different rainfall intensities

sheet flow erosion varied similarly with rainfall process and can be described with power functions. Sheet flow erosion increased with rainfall duration increasing. ( 2) Under different slope gradients

sheet flow erosion increased with rainfall intensity increasing and can be described by linear equations. ( 3) Under different rainfall intensities

sheet flow erosion modulus increased firstly and then decreased with soil gradient increasing. Their relationship can be described by log-linear equations. ( 4) Under different rainfall intensities

the relationship can be descried by power equations. ( 5) Under different rainfall intensities

slope gradients

and slope lengths

sheet flow erosion can be described by ternary linear equations. Rainfall intensity affected erosion modulus most greatly

followed by slope gradient

and slope length behaved minimal impacts.