Abstract: Mudstone roof of 10^# coal layer in a coal mine of Shanxi province is influenced by upper goaf water, and roof watering, disintegration and serious roof collapse occurred in the excavation process of 10^#+11^# united coal roadway. Due to rock crushing and water damage on the anchor, conventional support means are difficult to obtain a good supporting effect. So, advanced grouting technology is proposed for water softening mudstone if signs of water softening are found in rock by using coring exploration technology before heading. Theoretical analysis and industrial tests were made for the arrangement of holes, grouting parameters and grouting technique. According to the analysis of water blocking rate, physical and chemical properties of wall rock, rock displacement, the results showed that: advanced pre-grouting is effectively in intercepting water, reinforcing roof, improving the overall stability of the rock, and ensuring safe and fast roadway excavation.