Chitinase, a potential pathogensis- related portein, was induced in the leaves of 30 day - old bean( phaseolus vulgaris ) plant with the treatment of 10 $mu $ /mℓ ethylen for 30hrs. Chitinase was purified from the mature tissue of bean leaves( phaseolus vulgaris ) by ammonium sulfate precipitation followed by affinity chromatography on a regenerated chitin and sephadex G-75 chromatography. The purified chitinase gave a single band SDS- PAGE to be 32,000 Dalton. In order to elucidate the three- dimensional structure of chitinase and to shed light on the functional mechanism of this class of enzymes, the enzyme was tried to crystallize( Sitting Drop Method). Crystals grew at room temperature to their final size within two weeks(0.2mm $ imes $0.2mm $ imes $ 0.1 mm ), This enzyme are still continuing to crystallize for the study of X- ray.