With the support of remote sensing and ecological function analysis, effects of wetlands changes on ecoenvironmental water requirement in Liaohe delta were calculated. The result showed that the change of gross ecoenvironmental water requirement did not exceed 3% that of 1988. At the same time, the changes of water requirement of various wetlands were very obviously which caused by area changes of all kinds of wetlands. The sort order of water requirement of per square kilometer is river-canal, lake-pond-reservoir, fishery land, paddy field, bulrush and supra-tidal zone. The research of this article not only can offers effective basis for calculating eco-environmental water requirement in water resource programming which are relative to protection of wetlands and adjustment of regional agricultural structure, but also can use for reference by other region.