Abstract: The super burst water occurred in Maluqing Tunnel of Yichang-Wanzhou Railway on January 21，2006， which would be the largest burst water in China history of railway construction. The flow rate was more than 200 m3 / s and the total water inflow was more than 100 104 m3 . This phenomenon occurred again and more than once after that accident. Based on the burst water in Maluqing tunnel，it was analyzed its characteristics. This supper water inflow be defined karst water burst flood. By research on the law of karst geology，the geologic genesis of water burst in deep tunnel can be got. The Mechanical mechanism of stability of surrounding rock was studied. On the basis， tunnels geological factors and engineering treatment method was got.