A thermophilic strain NR615 possessing cellulase was isolated at 60℃ from hot spring samples.Based on the ITS sequence and phylogenetic tree analysis,strain NR615 was identified as Aspergillus fumigatus.The strain was capable of growing well at 28~60 ℃.According to optimization condition of cell growth and enzyme production,the initial pH is 6.5.The supernatant of strain incubated medium showed efficient activity of cellulase with addition of crystalline cellulose as carbon and beef extract as nitrogen sources respectively.The highest enzyme activity at 2.41 IU/mL was reached after incubation for 5d.The optimal pH of the celullase for the reaction is 5.0.This enzyme shows stable activity over a broad range of temperature from 50 ℃to 70 ℃.These characteristics of the cellulase demonstrated that it has potential application in the thermostable cellulase field.