The borehole coring and the water pressure test are reliable means for judging the construction quality and impermeability of massive concrete in water retaining structures. Method of roller compacted concrete(RCC) gravity dam of Wuxikou hydro-junction project with core drilling and water pressure test for the detection of construction quality of roller compacted concrete. This paper introduces the design of concrete partition of the Wuxikou RCC Dam , the experimental scheme of drilling water pressure and the selection of drilling position , the quality of roller compacted concrete was evaluated by the statistical analysis of the appearance, level and seam surface bonding quality, core fracture rate, water penetration test and so on, according to test conditions, the paper puts forward some suggestions on the borehole coring and the water pressure test of RCC dam.