Abstract: This article is based on the wetk done in 1982-1984 on the western slop of the northern section of Ailao Mountain (the Taizhong district of Jingdong County，Yunnan province，24°32′N & 101°01′E)．The aim is to compare the effects of different intensity lumbring on the changes of the Hemipterous insects in the forest of Pinus keisya uar．Langbianensis and P．Yunnanensis，which present 3 types(the plants:1.are kept well；2．Are lumbring terribly and 3.are lumbring completely) in 6 plots．The results are as follows:1．Among the 380 heads of Hemipterous collected in the 6 insects plots mentioned above in 1982-1983，there are 15 families，51 genus，64 species of which 13 families，32 genus and 36 species collected in the forest of Pinus keisya var．langbianensis and 15 families，37 genus，46 species of P．Yunnanensis．2．The increasing of felling trees decreases the families，genus，species，diversity，richness，evenness and individual number of Hemipterous inseets．3．According to the relative and regression analysis．The P．Keisya var．langbianensis r=0.9916，P.yunnanensis r=0.9933，Y_(shi)=0.3910X_(shi)- 4.3670,Y_(yun)=0.4655X_(yun)-3.9492．This showed that there was a relationship between the richness of plant and that of Hemiptera，and that protection of forest coverage is very important．4．The structure and space structure of the plant communities are two important factors which influence and decide the population，diversity,richness，evenness and variation of the．Individual number of insects．The various degree of lumbring destroyed directly these two structure leading to a redistribution of the community and population structure and changes in number and species，and through the web and chain of food indirectly affected the whole community of insects evell breaking down the natural ecological equilibrium．