The present invention relates to polyalkylsilsesquioxane particulates and a method of preparing the same, and more particularly provides the polyalkylsilsesquioxane particulates, of which moisture content is low, water repellency is high, and hygroscopic property in storage is low, and a method of preparing the same by end-capping silanol groups (SiOH) on the surface of the polyalkylsilsesquioxane particulates with alkyl groups by adding an alkoxytrialkylsilane having a triorganosilyl group thereto.