Abstract: Through the analysis of the effect of repeated support from hydraulic support (double sections) upper beam at longwall high filling water of 1126 working face on the roof strata. Research of the strata behavior law of the high water material filling method shows that the thickness of the immediate and main roof strata will change due to the alteration of the rock stress in the mined-out area; the stability classification of the immediate roof strata drops from the level four down to the middle place between level one and level two; the rock pressure of the basic roof strata transformed from level there to level one.