The invention discloses a method for improving smooth blasting effect of coal mine tunnel tunneling, and is suitable for coal mine tunnel tunneling blast. A cotton thread with a fixed length is connected with a water cannon mud bag to control the guiding depth of the water cannon mud bag, so that an air column between the water cannon mud bag and a hole bottom cartridge is preserved; after water cannon mud is installed on site, when holes are sealed and plugged with clay cannon mud, the water cannon mud is pulled through a tension cotton rope so as to fix the position of the water cannon mud, and the mud capping length is ensured so as to meet the requirement of coal mine safety rule on cannon mud sealing and plugging length. An air column type charging structure of smooth blasting of coal mine tunnel tunneling can be realized, the blasting damage to surrounding rocks during tunnel blasting engineering with bad light blasting effect such as soft and broken surrounding rocks can be reduced, and good smooth blasting effect is obtained. The method is simple, convenient to operate and good in effect.