Abstract: In order to reduce the use of cement in grouting materials and develop new grouting materials,fly ash and slag as the precursor,using alkali excitation method to prepare geopolymer grouting materials. The polypropylene fiber was added for performance optimization of grouting material,and the effects of polypropylene fiber on the workability,mechanical properties and microstructure of geopolyolytic grouting materials were studied. The results showed that the addition of fiber can increase the setting time and decrease the fluidity of geopolymer grouting material. The addition of fiber can significantly improve the compressive strength,flexural strength and frost resistance of geopolyster grouting material,and reduce the drying shrinkage rate of the material. Comprehensive test results showed that the optimal fiber content is 3%. The microstructure test results showed that the microstructure of geopolymer grouting material is more uniform and compact after adding fiber. Fiber can be used as micro-aggregate in geopolymer grouting material to optimize the properties of the material.