A mutant strain ZH-g was screened by He-Ne laser mutagenesis on the cells.Its pectinase activity was in 1.3 fold of the original one,reaching 301 μ/mL.On the basis of this,using He-Ne laser irradiating on the protoplasts of ZH-g,the mutant strain ZH-gA with high yield of pectinase was obtained.It accumulated pectinase activity up to 357 μ/mL which was 18% higher than that of the parent strain.This strain can produce pectinase efficiently under both aerobic and static cultivation.The enzyme activity is stable after several times of batch.