Quasi-vertical ZnS nanostructures with different Ga doping level ( ZnS:Ga nanowalls ) have been synthesized in high yield from the mixed powders in the vacuum furnace at 1150 oC. ZnS:Ga nanowalls were grown vertically on the substrate with the size in the range of several microns and the thickness down to 15 nm and have very rough edges. The possible growth mechanism of nanowalls is likely governed by a vapor-solid (VS) growth mechanism. Room-temperature cathodoluminescence spectra of ZnS : Ga nanowalls show two emission peaks at approximately 443 nm and 578 nm. The emission mechanisms are discussed.