Abstract: Sand-proof pillars in the Neogene and Quaternary thick loose formations and weak aquifer water abundance formed a loose aquifer pressure-holding structure under special geological conditions such as thethin bedrock interface incline and undulation. The high water pressure of the aquifer in the structure causes sand-proof pillars are subjected to high water pressure impact,resulting in water inrush,sand inrush significant increases in and mine pressure. Theoretical analysis methods were used to explain the concept and formation reason of increased pressure-resistant sand-prevention coal and rock pillars,and to evaluate the reducingfriction coefficient by water sand. The impact of "high water pressure core" on the support resistance is also evaluated. The results indicated that the increase of support resistance of working surface during the waterand sand inrush is due to the reducing friction coefficient by water sand and the impact of the "high water pressure core". The friction coefficient reduction under different conditions was obtained. The impact calculation formula of the high water pressure on the support of the working faces was established based on the law of conservation of mechanical energy. The 11071 working face was used as an engineering example to calculatethe variation process of the support resistance on the working face. The results show that due to the decrease of friction coefficient and the impact of high water pressure the load acting on the support is increased,andexceeds the maximum load. The mine pressure of the working face increased during the water and sand burst process.