Purple soil sloping farmland is the important land resources in three gorges reservoir region. Based on the research of rainfall intensity influencing on runoff yield and sediment yield

the demonstrated and popularized intercropping orchard-pasturage model was taken as research object

and its characteristics of soil and water loss was studied through opening and locating monitor experiment. It's showed that:(1)The short period and high intensity rainfall has the strongest influence on runoff yield and sediment yield

there was obvious negative correlation between rainfall period and runoff yield and sediment yield

and obvious positive correlation between rainfall intensity parameters and runoff yield and sediment yield;(2)Among the rainfall characteristic parameters

average rainfall intensity is a best one to reflect runoff coefficients

silt amount and silt content of runoff

and I_(30) is the best one to reflect the change of runoff amount in purple soil sloping farmland;(3)Under different rainfall intensities

intercropping orchard-pasturage model can obviously reduce the runoff amount

runoff coefficient

silt amount and silt content of runoff

especially under the low intensity rainfall

its effect of water and sediment reducing is more obvious

and growing year also has influence on its effect;(4)Under the typical short duration and high intensity rainfall

intercropping orchard-pasturage model play an important role in time-delaying and postponing process of runoff yield and sediment yield;(5)Intercropping orchard-pasturage model has reduced surface soil nutrient waning after rainfall

and surface soil nutrient running off was decreased;(6)Intercropping orchard-pasturage model can reduce nutrient loss effectively

so as to keep soil fertility and improve soil productivity of purple soil sloping land.