[Objective] The responses of natural and artificial grassland to different types of erosive rainfall in loess hilly region of Western China were researched to provide guidance for vegetation construction and soil erosion control in this area.[Methods] Based on the data measured in 2007-2015 from runoff plots located in Anjiagou catchment

Dingxi City

we analyzed the influences of erosive rainfall on the erosions on 20° slopes of artificial grassland and natural grassland.[Results] In the study area

the erosive rainfall mainly occurs from May to September

and is greater in July and August

and correspondingly the amount of erosion caused by it is more than 70% of the annual erosion. Erosions observed on the two different types of grassland were both finely correlated with PI10. The erosive rainfall mainly refers to moderate rain and heavy rain

the amount of erosion caused by the two intensity rainfalls accounts for about 86% of the annual erosion. The erosion amounts observed in artificial and natural grassland caused by moderate & high intensity rainfalls were 90.8% and 91.2% of total erosion amount

respectively. The amount of soil erosion can well expressed by power function with PI10

PI30 as independent variables. Rainfall with 300 MJ·mm/(hm2·h) or greater erosivity caused the largest proportional soil erosion

for artificial and natural grasslands

the proportion was 32.3% and 33.4%

respectively; rainfall with erosivity of 50~100 MJ·mm/(hm2·h) was most frequent

the erosion amount proportions were 26.0% and 29.1% of the total observed erosions

respectively.[Conclusion] The lower amount criteria of erosive rainfall for artificial grassland(coverage of 75%~82%) and natural grassland(coverage of more than 80%) were 11.3 mm and 11.9 mm

respectively; and the maximum I10 were 10.4 mm/h and 11.7 mm/h

respectively. The natural grassland has better effect of soil and water conservation than artificial grassland has.