Abstract: By numerical simulation and field measuring, overburden strata movement law of thickening coal seam in 4320 fully mechanized mining face of Daizhuang Mine was done. The results show that stress concentration occurs at two sides of the working face and the thickening zone during mining in numerical simulation tests, the roof of thickening zone has a large relative subsidence, serious plastic failure, roof broken, and the plastic zone enlarges with the mining of model; the first weighting interval is 22.8 m and the periodic weighting length is 11.8 m averagely in 4320 working face, and the influence scope of advanced abutment pressure is about 50 m in front of the working face; the roof of the thickening zone is broken and difficult to be controlled for stress concentration, but has little affect to the overburden strata movement.