An attempt has been made to obtain high tensile strength and ductility by grain refinement and the homogeneous dispersion of quasicrystals and intermetallic compounds through plastic forming of Mg-Zn-Y alloys. The alloys were hot rolled at 5 % per pass for a total reduction ratio of 80 %. Though cracks are observed around intermetallic compounds in hot rolled specimens, the specimens exhibit increased ultimate tensile strength, proof stress and elongation at room temperature compared to as-cast specimens. To prevent the occurrence of these cracks, the specimens were subjected to homogenization treatment at a higher temperature of 400 degreesC in order to dissolve the compounds that generate cracks during hot rolling. This makes it possible to carry out hot rolling at a high specimen temperature of 400 degreesC without cracking around the compounds. As a result, the elongation increases remarkably compared to the specimen that was hot rolled at 315 degreesC. However, the tensile strength is not significantly affected due to higher hot rolling temperature.