Abstract: A process for preparing nano water paint comprising the steps of: A. Modifying the chemical property on the surface of nano particles by hydroxylation for forming hydroxyl groups at high density on the surface of the nano particles; B. Forming self-assembly monolayers of low surface energy compounds on the nano particles by substituting the self-assembly monolayers for the hydroxyl groups on the nano particles for disintegrating the clusters of nano particles and for forming the self-assembly monolayers homogeneously on the surface of the nano particles; and C. Blending or mixing the nano particles having self-assembly monolayers formed thereon with organic paint to form nano water paint.