SCS model is a small basin design flood model proposed by Soil Conservation Service （SCS） of USDA. At rainfall-runoff relationship

SCS model gives consideration to land used

soil type and antecedent soil moisture. Because the model tallies with the actual situation at rainfall runoff computation and is simple in structure

this model finds wide application. But soil classification and Runoff Curve Number （CN） in the model are restricted by region

it isn’t suited to China. In this paper

we propose the formula to calculate the initial abstraction （Ia） and potential maximum retention （S）

as well as the soil type classified by soil texture and application of remotely sensed data. The rationality of improved SCS model is proved by rainfall-runoff calculation in Chuzhou exprimental basin

Anhui province.