Abstract: A Thermophilic Bacillus strain for secreting thermostable neutral protease was isolated from high temperature soil sample.The purification steps included 80% saturated ammonium sulfate sedimentation first,then with DEAE-Sepharose fast flow anion exchange chromatogram and Superdax 75 gel filtration on AKTA purification 100 protein liquid chromatogram system,and the final purification-fold 4.36 and recovery rate 5.31% were obtained.The molecular mass 30.6kDa was estimated by SDS-PAGE.The optimal pH and the protease temperature were 7.5 and 65℃,respectively.The protease was stable at 50"C during for 1 h incubation.The protease was inhibited markedly by serine protease inhibitor PMSF（phenylmethylsulfonyl fluoride）and metal ion chelator EDTA（ethylene diamine tetraacetic acid）.Andalso the protease activily is enhanced by Zn2+.So the protease belongs to Zn2+activated serine protease.

Key words: neutral protease, purification, characteristic, Thermophilic Bacillus, serine protease