Based on the field experimental observation and lab analytical tests, this paper analyses and studies the biological benefits from the cultivated slopping farmlands after the comprehensive controllin water and soil losses, and its biological benefits are shown in the following aspects: 1.the remarkable reduction of water and sediment losses; 2 .an increase in vegetation cover so as to improve microclimate in the fields; 3 .an obvious enhancement in soil ability to store moisture and con- serve moisture in soils;4 .farmland ecosystem begins to convert into a better cycle， and 5.the diminishment of natural disasters and the enhancement in the hability to resist disasters in agriculture.