Abstract: According to the seam reservoir featuresof the low porositylow pressure,/ow water saturation and high metamorphic degree and the desorption dificultconditon of calbed methane in the screen pipe and completion in aiyuan Mdine, n orderto realize therequirements of the gas control and coalbed methane joit development,a compleed gas output improvement and reconstrucion tehnolgy by nirogen ineclion was discovered under the scren pipe and completion of the coalbed methane horzontal well.with the different features ofthedislaced drainage liquid.ntirogen displacement,suppressed well and blowout three nirogen reconstrucion modes appied,ntiti tragen injecton.pressure suppressed.b1owout operations were conducted.W ith the ntrogen injecion reconstruction.thepaoliton near the well coud be cleaned.the sean cleat cracks coud be linked up.,the seam pemealilt far from the mine shaft asimproved ,a single phase gas seepage channel was established and the high eficient development target of the coalbed methane was realized.The results showed that afer the gas outut improvement and reconstouction technologyof c albed methane horizontal well ly ntrogen injecion in Qilyuan Mine was used,a dail gas production of a single well was improved by 3 ~ 201times and a breakthough of a single well production was realized.