Abstract: To increase the effect of prevention and control of water hazard formed by overburden stratum separation, the characteristics of dynamic and periodical water inrush caused by the burst of water cells were analyzed.Using mechanical analysis method, combining with the critical layer theory, a discriminant for the produce of overburden stratum separation was deduced.The formation process of bed separation was simulated, and the periodicity of water inrush caused by the burst of water cells was summed up.The study results show that the overburden stratum separation is caused by the bending and sinking of overburden strata inconsistently.With the advance of working face, the separation develops to maximum after formation.When there is enough water above the separation, water formed by overburden stratum separation appears.At this time, if the height of water flowing fractured zone is large enough to guided bed separation water, the water will collapse and cause mine water disaster.Then, the separation will gradually be compacted and shrink, the water will drain up in the end.With the roof of coal seam periodically breaking, water hazard formed by overburden stratum separation appears periodically.The scales of dynamic and periodical overburden strata separation are different.The largest one is the first occurred separation space, and the water hazard is most serious.The water inrush caused by the burst of water cells formed by overburden strata separation happens one time with the length of working face advance 100 m in the research area.