Abstract: Because of coal pillars supporting, roof in triangle area of haulage roadway and ventilation roadway easily presents hanging arch when fully mechanized coal face is mining, which threats safety production of mining face. Using carbon dioxide gun to proceed to presplitting blasting experiment in hanging arch in triangle areas of fully mechanized mining face roadway, the problem of hanging arch in triangle areas of mining face roadway is solved effectively, which eliminates produced storm and extrusion harmful gas from roof caving, achieve good effect and safety production.