Abstract: Through the similar simulation experiment of mining above aquifer, the vertical stress distribution and deformation characteristics of floor aquifuge are analyzed, and the change laws of vertical displacement values about floor aquifuge in goaf is acquired. The result shows that the fissure zone height of overburden is gradually increased and the pressure of floor in the goaf is also accumulated. When the pressure of floor is too small to restrain the confined water, the deformation value of floor aquifuge is gradually increased with working face advancing. So it needs to consider the failure characteristics of overburden with working face advancing after the first weighting when the safety mining of confined water is evaluated.