Abstract: Shortage of water resources is likely to result in conflicts among the water resources supply and demand system the socio-economic development and the eco-environmental requirement.In this study,the principle of order is used to balance and coordinate the three conflict parties.This is done through the introduction of order parameters to the three parties.A system identification model is developed based on the concept of the degree of order and coordination.The results to the Dongjiang River Basin to reveal the evolution of the water resources supply and demand system.The results show that the water resource supply and demand of Dongjiang River Basin has evolved towards disorder and chaos state under the strong disturbance of human activies in 2000.