Pseudoscraena crocea growth hormone(pcGH) was expressed in Pichia pastoris expression system.By using the principle of preference of the yeast codon,the pcGH gene was changed into its synthesis gene of preference of the yeast codon.The expression vector pPICZ A-GH was constructed successfully.And the gene was integrated into Pichia pastoris strain X-33 by using chemical conversion technologies.The expression of recombinant fish GH has been reached 340 mg·L-1.