Using primers designed from the sequence of endoglucanase CelB gene(GenBank Accession No.: D83732.1) from Aspergillus oryzae,endoglucanase eg was amplified through PCR with Aspergillus oryzae giF-10 genomic DNA as template.The Aspergillus oryzae giF-10 endoglucanase eg gene was inserted into the yeast expression vector pPICZαA,then the pPICZαA-eg plasmid was electroporated into yeast competent cells of X33 host strain and a lot of positive transformants were obtained.Hydrolysis cycle tests proved that the gene could be expressed successfully.The SDS-PAGE showed that the molecular weight was about 65 ku.In the condition of shake flask culture,fermentation conditions of yeast expression engineering strain were optimized.The results showed that the optimal concentration of methanol induction was 0.75%.After five-day induction culture with 1L flask,it reached the highest activity 120 U/mL.The optimal pH and temperature of the recombinant enzyme were pH 4.0 and 45 ℃,respectively.In the range of 30~45 ℃ and pH3.4~6.9,it could maintain more than 70% of the highest endoglucanase activity.