According to attributes of ecological water requirements, evaluation methods of river ecological flow was proposed in terms of water quantity and water quality. The water quantity evaluation methods included water resources utilization ratio method, measured runoff method, consumption coefficient method; and the water quality evaluation method was established based on wastewater-runoff ratio factors. The standards for water quantity and water quality evaluation were also proposed. Seven major basins of China, including the Songhuajiang River, the Liaohe River, the Haihe River, the Yellow River, the Huaihe River, the Yangtze River, and the Zhujiang River, were studied as examples by using the above methods. The results indicated that if these rivers were evaluated merely from water quantity, the ecological flow is lower than the water requirements standards in the Haihe River and the Yellow River; however, if these basins were evaluated at the same time of water quantity and water quality, the ecological flow is higher than the water requirement standards only in the Songhuajiang River, the Yangtze River and the Zhujiang River. These showed that actual ecological water shortage could be revealed only by evaluation methods on the basis of "water quantity" and "water quality" in China.