Abstract: With konjac purified powder as experimental material,using ultrasonic method,citric acid method and cellulose enzymatic hydrolysis method,the degradation process parameters of konjac glucomannan were optimized by the orthogonal test,and these three methods degradation efficiency of konjac glucomannan were compared in this paper. The results showed that cellulose enzymatic hydrolysis degradation was the best,and the optimum conditions were as follows :material-liquid ratio was 1.0g/L,dosage of enzyme was 0.25g/L,temperature was 50℃,and enzymatic hydrolysis time was 100 min.