Based on the related literature and the analysis of the relationship between wetland ecosystem and hydroperiod, the estimating and classifying methods of eco-environmental water requirement for wetlands are established. The data collected from Huang-Huai-Hai Area are from the electronic map (1∶250000) of China National Topographical Database of 1997 and the historical statistics since the 1980s.The results indicate that the minimum eco-environmental water requirement for wetlands is 16.98×109 m3 and the optimal one is 38.38×109 m3 in the studied area. For the five wetland nature reserves covered in the area, the values are 1.47×109 m3 and 3.31×109 m3 respectively. The comparisons of the mentioned minimum water requirement with the status water use, which is 17.05×109 m3 for wetland ecosystem (1997 as the status year), suggest that the water use has not met the minimum eco-environmental water requirement in the Haihe and Huanghe Basins of the studied area. However, the status water use guarantees and exceeds the minimum eco-environmental water requirement in the Shandong Peninsula and the Huaihe Basin. Based on the eco-environmental programming and water resource planning of the studied area, the study establishes the water requirement of the year of 2010, 2030, 2050, when the eco-environmental water requirement for wetlands is 18.30×109 m3, 21.64×109 m3 and 26.76×109 m3, respectively.