To study recycled trashes from shrimps and crabs in the sea through chitinase secreted by microor-ganisms, the chitinase gene chit2 was cloned and sequenced from Beauveria bassiana by the polymerase chain reaction (PCR), and was ligated into the yeast expression vector pYES2. The expression vector plasmid was transformed into Saccharomyces cerevisiae H158. Gene expression took place upon induction with 2% galac-tose. The measurement of enzyme activity shows that the expression production can be expressed in active forms and secreted to the medium. The enzyme activity approaches the peak of 0. 63 U/mL when the culture time is 36 h.