The purification of elastase was achieved by combination methods of ammonium sulfate precipitation,ion-exchange chromatography and gel filtration chromatography.The elastase was purified 13.79-fold to apparent homogeneity with 7.88% overall recovery.It was a single-chain protein with a molecular mass of 31ku,and estimated by SDS-PAGE and gel filtration.Studies on enzymatic properties showed as follows:the elastase belonged to metalloproteinase containing Ca2+.The elastase activity had a temperature optimum of 50℃ along with good thermal stability.Meanwhile it was optimal at pH 7.4 in borax-boric acid buffer or pH 8.6 in Tris-HCl,and tended stability between 8.0 and 11.0.10mmol/L Ca2+ had stabilizing and activation on the elastase activity,whereas SDS and Tween-80 only had activation.Moreover,the elastase activity was inhibited varying degrees by many irons(Li+,Na+,Zn+,K+,Ba2+,Mg2+,Mn2+)and EDTA.The catalyzes dynamics equation was:y=0.186x+ 32.493,Vmax =0.0308 U/mL,Km=0.005 7g/mL.