An expression cDNA library was constructed from high-yielding glucoamylase strains of A.niger and the glucoamylase gene was isolated,then the expression of the gene in Pichia pastoris was studied.The cDNA sequence of glucoamylase from A.niger was obtained by RT-PCR.The cDNA fragment was cloned into the expression vector pPIC9K and the linearized recombinant vector was transformed to Pichia pastrois GS115 by electroporation.The positive clones were analyzed subsequently.The recombined Pichia pastrois were cultured in the MM medium,using 1% methanol to induce the expression of recombinant gene.The results showed that the maximum activity of glucoamylase was 15.6 U/mL after it was fermented for 72 h.Sequence analysis revealed that glucoamylase had 1908 bp,which encodes a putative polypeptide of 636 amino acids.The expressed protein was purified from the fermented supernatant using DEAE column and determined by SDS-PAGE.The result of SDS-PAGE also showed that the molecular weights of the enzyme was 80 kDa.The expression vector of the glucoamylase gene was constructed successfully,and it could express glucoamylase in Pichia pastrois.