The runoff in five different surfaces was observed in Sunjiacha basin of Yuzhong County in Uansu Province

and the relationship between specification of leve-terrace preparation and rainfall in semiarid loess hilly region was studied.The results showed that the runoff in mowing grass plot was 9.77%-24.87% higher than that in original barren slope plot.In comparison with barren slope plot

Tamarix mongolica plot and Caragana microphylla plot were capable of decreasing the runoff for 8.28%-60.57%and 12.24%-78.41%

respectively.The depth of runoff after individual rainfall had a great linear relationship with rain-fall intensity.The level terraces were definitely able to increase the rainfall conversation.The configuration of level terraces should be under the consideration of maximum 6 h rainfall within five years.In this case

the level terraces ridge should be 0.1 m

with the slope length of 3.9-8.2 m.Heightening the ridge properly will raise the efficiency and protection area of level terraces.