In this study,a high cellulase activity strain,Pseudomonas fuchunensis N32,was screened.The fermentation conditions were optimized by single factor and orthogonal design,and then the fermentation tank was used to expand the culture.Finally,the enzymatic properties of N32 were studied.Finally,the enzymatic properties of N32 were obtained.The results showed that the optimum conditions of enzyme production were as follows:culture time was 3 days,carbon source was starch,nitrogen source was yeast powder,initial pH was 5.0,liquid volume was 100mL,the culture temperature was 30℃,inoculum amount was of 2.0%,the speed of shaking table was 160 r/min.The optimal combination was A₃B₂C₂D₂E₁F₃G₃,i.e.,initial pH was 6.0,the speed of shaking table was 140 r/min,the culture temperature was 35℃,liquid volume was 125 mL.The study of enzymatic properties showed that the opti-mum temperature was 30℃,and the optimum pH was 4.0%,Na⁺、Cl^-、NO₃^-、CH₃COO^- had a activation effect on CMC,while K⁺,Mg²⁺had inhibition effect on CMC activity.Urea,EDTA,SDS had inhibition effect on CMC activity,and EDTA had the strongest inhibition effect.