Five-dimensional characteristics of a natural-social dualistic water cycle system were analyzed. The entropy theory and the synergetic theory were used to evaluate and compare the multidimensional regulation scenarios of the water cycle system. Dominant factors(order parameters)of multi-attributes were regarded as the evaluation indices for the regulation scenarios. A quantitative relationship between the evaluation indices and the five-dimensional characteristics of the water cycle system was established. The evaluation indices of system coordination degree and integrated distances of order degree were established for regulation alternatives in order to quantitatively evaluate the effects of multidimensional regulation and to determine the optimal scenario. The feasibility of the proposed methods for scenario evaluation and optimal selection for multidimensional regulation of the water cycle system were verified through a case study in the Haihe Basin.