After the inundation of shaft in Chengchao Iron Mine,large area collapse of development openings caused serious influence on production.Based on test and research on the types and contents of clay minerals contained in ore rock and their crumbling and softening properties,this paper analyzed the degree and ways of stope drift wallrock deformation affected by water,found out the major cause for the large area collapse of openings.This offers important reference value for the cause analysis and comprehensive control of opening collapse in similar skarns mines.