Abstract: Abstract: Serious floor heave had occurred of the west track roadway in Tingnan Coal Mine. The maximum value of floor heave arrived to 50 cm, which impacted the normal application of roadway severely. The article involved engineering geology and soft rock engineering mechanics etc, employed the ways of study on engineering geomechanics, laboratory testing, and deeply researched the deformation mechanism and generating process of floor heave, it shows clearly that the major influencing factor that led to floor heave is the horizontal extrusion stress, then floor surrounding rock with high content of swelling clay minerals and soaking effect on floor rock, so the deformation mechanism is compound type of floor heave caused by the combined action of plastic extrusion and swelling. Aimed at the above-mentioned mechanism, provided the new support measures with inverted arch and floor bolt to control the floor heave. Project protice has shown good results of new supporting have been obtained with expected effects, and controlled the floor heave effectively.