Abstract: To study the effects of konjac planting on the soil anzyme activity of two kinds of pear plamtations,taking pear woodland without planting konjac as a control,studies were made of the activity of urease,invertase and phosphatase in soil of different forest lands. The results showed that the effect of planting konjac on the activity of urease and phosphatase in the pear forest soil was not significant,but invertase activity had a significant increase. The phosphatase and invertase activity in Changji pear forest soil after planting konjac did not change significantly,and yet urease activity decreased significantly; invertase activity decreased significantly after plowing Changji pear forest soil,urease and phosphatase activity did not change significantly. As could be seen the effect of konjac planting in pear woodland on soil enzyme activity was not significant. But real tillage would make the soil enzyme activity decrease significantly.