With the growth of population and economy, water demand has increased significantly in all the over world. However, the water consumptions in Haihe River basin located in the Northern part of China has decreased in recent years. Haihe River basin, covers the provinces of Beijing and Tianjin and parts of other six provinces of China is considered as the center of politics, economics, and cultural of China. Therefore, decreasing water demand in Haihe River basin has attracted the attention of hydrologists and decision makers. A study has been carried out in this paper by using information entropy theory to understand the possible causes of changing water consumptions in Haihe River basin. Results show that entropy value of water consumption system of Haihe River basin has increased from 0.72 in 1980 to 0.91 in 2008. The balance degree of water consumptions has also increased from 0.68 in 1980 to 0.89 in 2008. The results indicate that the water consumption structure of the basin has become more stable with time. The dominance of agricultural water consumption has weakened, the industrial consumption has stabled, and the domestic and ecological water consumptions have increased. The study reveals that land conversion from agrarian to industrial and higher water efficiency in industrial production have reduced the total water consumption in the basin. Water management approaches base on total quantity control and quota management have been proposed in this study for further reduction of water demand in the basin.