Abstract: In the increasingly complex and harsh geological environment, the quality requirements of grouting reinforcement are getting higher and higher. It is of great theoretical significance and research value to establish a scientific and reasonable grouting effect evaluation system. Aiming at the grouting effect detection methods widely used in projects such as grouting amount accounting method, inspection hole analysis method, P-Q-t curve method and geophysical detection method, the hierarchical evaluation system is established by extracting the primary and secondary influencing factors, and the mathematical model for grouting effect evaluation is built based on expert opinions and actual working conditions; Then, based on the basic principle of fuzzy mathematics, the weight vector is quantified as the weight of evaluation factors, and the mathematical expression of fuzzy phenomenon is realized through matrix operation, so as to complete the accurate evaluation of grouting effect in sandy soil tunnels; Finally, combined with the sand tunnel of Zhengzhou Metro Line 7, through the comprehensive analysis of fuzzy evaluation, it is considered that the grouting effect grade is good. During the actual excavation of the tunnel, there is no hydrological and geological interference in any form, which indicates that the evaluation method is scientific and efficient and can provide guidance or reference for other engineering construction.