Abstract: The 4^# coal seam floor is the soft rock mainly on aluminum mudstone in the main mining seam of Dafosi Coal Mine, floor heave is induced by many factors during roadway mining. By analyzing the floor heave mechanism, the physical and chemical composition, the surrounding rock force of 40110 working face roadway, it determines the type of roadway floor heave, and it is composite floor heave. On the basis of the original support, it increases cross-section roof and bottom corner supporting strength, and it uses the joint support form of pressure releasing groove and bottom corner anchor for the floor. Dynamic monitoring analysis by various means shows that the support effect is good, roadway floor heave is controlled within the allowable range.