The structure gene from Clostridium thermocellum ATCC 27405 encoding endoglucanase was cloned into expression vectors pET-20b( +) and pHsh to construct pHsh-celD and pET-20b-celD. In comparison,celD was over-produced in E. coli BL21-CodonPlus( DE3)-RIL by using plasmid pHsh in soluble formation,while it formed inclusion-body by using plasmid pET-20b( +). The results from SDS-PAGE showed that the molecular mass of the expressed recombinant celD was about 66 kD,which was exactly the predicted size. celD was purified by heat treatment and Ni-NTA affinity chromatography. The purified celD exhibited the highest activity at pH 5. 4 and 60℃,and retained more than 50% activity after incubated at 75 ℃ for 1 h. The cellulase activity of celD was significantly enhanced by Ca2 +and inhibited by EDTA. The expression vector system of the heat shock plasmid pHsh owned such advantages as high expression level and low cost for induction. Moreover the superior stability of the recombinant enzyme laid the base for the application of large scale fermentation.