[Objective] The regulation mechanism of different vegetation patterns on erosion dynamics in hill-gully slope was studied in order to provide a scientific basis for further revealing the law of erosion in grassland slope and the effects of vegetation on erosion reduction. [Methods] The regulation mechanism of different vegetation patterns on the erosion dynamics on a hill-gully slope was analyzed with rainfall simulation and three-dimensional laser scanning technology on a hill-gully slope model. [Results] Both runoff velocity and sediment concentration affected the dynamic process of slope erosion, and runoff velocity was the dominant factor. The gully-slope area was the main erosional sediment source. The scope and degree of vegetation regulation impacts with different patterns could be reflected by sediment yield ratios of hillslope to gully-slope. The grass strip located at the middle and lower part of the hillslope not only reduced the erosion degree effectively on the hillslope, but also retarded runoff velocity on the gully-slope greatly which would alleviate the erosion at the lower part of hillslope and gully slope. [Conclusion] Different vegetation patterns regulate the erosion dynamics in hill-gully slope by affecting the runoff velocity and sediment concentration.