Abstract: Based on meteorological data, land utilization, statistic data of industrial and agricultural production, by using the method of water quota and the Penman model, this paper calculated the ecological water amount and its component of Henan Province, and then analyzed its spatial variation by GIS. The result showed that, the average ecological water amount was 8248808×104m3, but the coefficient of variation was high. A larger value appeared in the Southern and Western mountainous region. The average ecological water density was 5910×104m3/km2, and coefficient of variation was smaller. The ecological water amount was mainly composed of ecological demanded water and water body storage, which relative to land utilization, meteorological condition, vegetation statue and regional area. The cluster analysis result indicated that ecological water of Henan Province could be divided into 3 regions, which were higher amount with lower density, lower amount with higher density, and lower amount with lower density, respectively.