Abstract: The longwall partial flexible filling mining method is an effective way to achieve water conservation mining in shallow seam. This article carried out the strike longwall mining physical simulation experiment, analyzed the stability law of impermeable rock group under space filling two strips. The conclusion showed that different filling space width and filling width would directly affect the upward crack development height and the stability of impermeable rock group under the invariable conditions of filling body strength and elastic modulus. Based on the physical simulation experiment, the article set up a stability mechanical model for special water conservation mining area partial filling impermeable rock group, and determined formula of upward crack development height.