Abstract: Based on the situation of serious shortage of water resources and the need of eco-environmental construction in the Loess Plateau, taking small watershed as research cell and rainwater resources as research object, the definition for potential of converting rainwater into water resources was put forward. The various potentials of developing rainwater resources and the relationship between sustainability and sustainable utilization of rainwater resources were analyzed. And the discrimination models for various types of sustainable utilization of rainwater resources were established. These results could provide the scientific basis for the high efficiency utilization of rainwater resources and eco-environmental construction in the Loess Plateau.