The gene of human thymosin alpha 1(hT(1)was synthesised according to favorite codons of Pichia pastoris by PCR. N-terminal 28 amino acid residues of 40S ribosomal protein (RP), S24E that is N-acetylserine were replaced by hT(1 for the constitution of hT(1-RP fusion gene in order to express acetyllated thymosin α1. And also,the Asn-Gly bond was designed to faciliate isolation of the target protein.The fusion gene was cloned into the expression vector, pPIC/9K. The constructs were transformed into HIS4 mutant strain GS115 by electroporation. Both SDS-PAGE analysis and Western blot analysis indicated that the fusion protein was expressed successfully.