The water spatial distribution diversity provides a new idea and method for the evaluation of surfacewater distribution，and the grid scale settig is the prerequisite for its research conclusions. Five typical caseareas in Henan Province were selected for a variation analysis of water spatial distribution diversity in 14 dif-ferent grid scales to explore the setting strategy of proper grid scale in the water spatial distribution diversitystudy.Results show that the best grid scale in the water spatial distribution diversity is between 2km to 500m.