Abstract: The proper skeleton and optimal structure of runoff farming system in small basin or valley and the experimental data of the flood-prevent and silt-control are presented. On the basis of the theory of slope runoff, the equation of runoff equilibrium on slope surface is created and the mean dis charge from slopes, which treated by different skills on the surface, is calculated. It is acknowledged that the pool-collecting system of precipitation and water conservation skills provided scientific evidences for improving eco-environment in arid areas, rehabilitating desertified lands, closing agricultural environment to control artificially and for finding new water supplies with lower cost and high quantity in dry land areas.