We report for the first time the controllable synthesis of monodispersed single-crystal ZnSn(OH)6(ZHS) polyhedral microcrystals (MCs) with five morphologies through a facile solution method without any organic agents. XRD, FESEM and FETEM measurements have been performed to illuminate the structure and morphologies of ZHS MCs. These characterizations indicate that the area ratios (R) of facet {111} to {100} of ZHS polyhedrons can be deliberately controlled from 0 to ∞ by the molar ratios of precursors (X). OH−, a simple ion, is proven to play an important role preferring {111} for the formation of polyhedral MCs, and the shape evolution experiments of different polyhedrons indicate that their kinetic formation mechanisms are different due to different amount of excess OH− in the solution. The tests of photocatalytic activity of ZHS MCs indicate that the {111} facet is more active than {100} for conversion and mineralization of benzene.