Disclosed is a genetically recombinant Saccharomyces cerevisiae useful for degrading and utilizing kitchen wastes. Genes encoding α-amylase (AMY), glucoamylase (GA) and acid protease (AP) were introduced into the genetically recombinant Saccharomyces cerevisiae using a Saccharomyces cerevisiae multi-gene co-expression vector and successfully expressed and secreted. The Saccharomyces cerevisiae so obtained are capable of secreting amylases and protease to degrade the starch and proteins in kitchen wastes to produce carbon and nitrogen sources such as glucose, polypeptides and amino acids, allowing fermentation into ethanol.