Abstract: Quick plugging and dynamic grouting technology under complex geologic conditions in mines is a technical problem in the field of grouting and one of the effective solutions is to develop new chemical grouting materials. Based on the reaction principle of polyurethane materials, we carried out the research and development on production formula of polyurethane grouting materials. By analyzing the polyurethane synthesis reaction temperature and the way of adding reagents as well as conducting contrast experiments on various auxiliaries and additives the best formula for the material was determined. It was found that the grouting material prepared by 4% nano silica modification had better performance, and high hydro-expansion rate, and reaction process and products were environmentally friendly and non-toxic by using phosphoric acid as retarder, ethyl acetate as solvent and PM-33 as catalyst. Our work is believed to provide a new type of one-component quick-set and expansion polyurethane grouting material for grouting under complex geologic conditions.