Abstract: According to the mine roadway failure problem occurred by the fault water inrush in the second belt conveyor roadway of No. II level in a mine,with the com prehensive analysis on the engineering geological conditions,the paper summarized the failure features of the mine roadway under the previous support and after the repai r. Based on the stress- seepage coupling effect,the paper analyzed the floor water inrush mechanism of the mine roadway and finally the paper discussed the water- rock a ffected to the weaken role of the muddy rock. The results showed that the surrounding rock of the mine roadway mainly was lumpy mudstone and the ilite was taken 90%. Under the role of the high pressurized seepage water, the volume of the mudstone would be increased by 50% ~ 60%,the mudstone would easily be soft and muddy and the instability of the mine roadway could be occurred. Based on the circumstances,the control technology including the muddy rock replacement,multi layer bolt + steel rope +「 einforced bar net + shotcreting combined support,excavation of the pressure released slot,repeated grouting and others was provided. The expected effect was obtained a nd the technology could provide certain reference significances to the mine roadway with the similar condition.