Cassava residues were taken as main raw material, Aspergillus oryzae and Aspergillus usamii were chosen as glucoamylase preparation, and response surface was used to optimize and analyze saccharification temperature, pH, rate of enzyme and total amount of Aspergillus (g/100g cassava residues) so order to find out the best operation conditon for cassava residues saccharification. It was found that the best operation condition for Aspergillus to saccharify cassava residues were as follows: saccharification temperature 70°C, pH 4, ratio of Aspergillus oryzae and Aspergillus usamii was 3:9, total amount of Aspergillus 10%, and it turned out to be a total reducing sugar content of 2.70g/L.