Abstract: In order to effectively control the roof water inrush of 16020 working face in Xin'an Coal Mine, the paper discusses the technical problems of the roof water inrush under the condition of the old empty water supply by using the knowledge of hydrogeology, coal geology, mining, grouting and so on. The results show that: first of all, through analysis of the water level, water quality, water temperature and other factors to accurately and quickly identify the water inrush source and water diversion channel, and then use curtain grouting to cut off the roof water supply channel in this roof water inrush treatment is effective. It took three months to successfully block the supply channel, and the water blocking was successful. For the roof water inrush with old air water supply, curtain grouting is an effective way to cut off the supply channel, the technology can be used for reference for similar roof water inrush.