According to the feeding preference of the pichia pastoris expression system codon, a high-expression codon is selected to be redesigned and synthetized into a novel porcine interferon-gamma mature peptide nucleotide sequence. A recombinant yeast expression plasmid pPICZalphaC-IFN-gamma is successfully constructed, so that the correct expression of the porcine interferon-gamma is achieved in the pichia pastoris, the porcine interferon-gamma is expressed more easily in the pichia pastoris, the expression quantity is higher, and the foundation is laid from the large-scale production of gene engineering.