Abstract: This article studies and aualyscs the ecological benefit of pure forests of Yunnan pine(Pinus·yunnanensis).The writers suggest the need of reforming the pure forests of Yunnan pine so as to raise the ecological benefit of the forests.The suggested measure is that the pure forests and its felling slashes,now available,be reformed and reforested into the mixed broadleaf-conifer forests accupied mainly with Yunnan pine.