This paper first studied the distribution laws of soil bulk density, wilting moisture of soil and field capacity in terms of time and space and the facters related to them. Then according to the standard of soil wetness which defines 40 per cent of the field capacity as heavy drought, 60 per cent as and 80 per cent as optimum, we have calculated the threshold values of soil moisture of various sail wetness for twentysix representative points in five districts. This vvill provide foundations for adobting different agricultural cultivation methods and managerial measures at different localities. In the end, a regionalization index system of agro-hydrological characteristics of soil has been set up for Gansu province by using the wilting moisture of soil as the leading index and the bulk density and field capacity as auxiliary indices. According to the regionalization index, we divided the whole province into five broad regions and twelve subre-gions, discussed the agro-hydrological characteristics of soil in each broad region, and put forward the appropriate measures for soil reclamation.