The paper makes a systematic and comprehensive analysis of the effects of shelterforest belt (network) on wheat output. The conclusions are as follows: 1. The negativeinfluence scope of forestbelt is about 1.5H～2．0H　(H is the average height of forestbelt). 2. The northern and western sides of forestbelt are heavily affected by forest crown, whereas the eastern and southern sides are lightly affected. 3. It can effectively reduce effect of root system by digging rootcutting ditch. 4. The average outputincrease rate is 7．7％ in the field with rootcutting ditch, whereas only 4．7％ in the field without rootcutting ditch.