This research involved an approach for construction and rapid selection of Saccharomyces cerevisiae polyploidy series strains via mating-type interconversion induced by the expression of HO gene and adequate cross. By crossing with specific mating-type strains and checking zygotes with an optical microscope,S. cerevisiae polyploidy series strains were conveniently screened. The results of PCR and Flow cytometry analysis further indicated that the polyploidy strains constructed in this research were accordance with the anticapation. Therefore,the method for construction and rapid selection of polyploidy series strains in this study was quickly and reliable.