Analysis of Influencing Factors on hydrolysis of cassava stalk to sugar with cellulase was studied by optimizing the technology conditions.The results showed that the best conditions of the preparation were: enzyme pH 4.5,temperature 45℃,enzyme concentration 2g/L,hydrolysis time 42h.Under the conditions,cassava stalk hydrolyzed by the enzyme could produce much more reducing sugar,and has the best effect.