Abstract: As a mollusk degrading the plant biomass rapidly, Ampullaria crossean can produce cellulose-hydrolytic enzymes. This brings us a new sight into the biological degradation of the plant biomass. Total RNA was isolated from the stomach of the mollusk Arnpullaria crossean by using polymerase chain reaction, cloning and sequencing techniques, a complementary DNA DY1300 encoding a low molecular mass glycosyl hydrolase has been identified. It contains a 882-nucleotide ORF encoding a 294 amino-acid protein. The percentage of similarity with the cellulase EGX gene sequence from Ampullaria crossean is 89.8%. Amino acid sequence-based classification has revealed that the putative protein belongs to the glycosyl hydrolase family 10(GHF10).