Neutral cellulase has important applications in denim biofinishing.A Pichia pastoris transformant with high activity of neutral cellulase was screened from 6 recombination transformants by fermentation experiment.The research on the neutral cellulase production by the P.pastoris recombinant was conducted under shaking flask condition,and the results were shown as follows: medium volume 30mL in 250mL Erlenmeyer flask,the initial pH 4.8 and uncontrolled during the fermentation process,inoculum volume 10% and methanol addition 1% every 24h which demonstrated an obvious enhancing effect.The above conditions allowed the activity of the neutral cellulase to reach 1144U/mL.The results from the study on enzymatic properties indicate that the appropriate catalysis conditions for the neutral cellulase from the P.pastoris transformant were pH 6.0 and temperature 50℃,and that Zn~2+ and Mg~2+ were activators of the enzyme but Fe~2+,Fe~3+ and Cu~2+ were inhibitors.The outcomes of denim biofinishing test reveal that the neutral cellulase from the P.pastoris recombinant could significantly reduce the backstaining of indigo onto denim and has a promising potential in industrial application.