When the large diversion channel is excavated directly on the slope of fractured rock mass without pre-reinforcement measures, the landslide is easily caused by rainfall.Pulsating grouting technology can control grouting and solve the outstanding problems effectively such as ineffective grouting and poor reinforcement effect of conventional grouting,which can be used as a prereinforcement measure for fractured rock slope.Taking the typical canal section slope of the main canal of Centianhe reservoir as an example,the failure mechanism of landslide dumping induced by slope excavation of fractured rock mass was analyzed;the 3D heterogeneous orthogonal structural plane network model was built considering the factors,such as the inhomogeneity and uncertainty of opening, distribution,and mechanical parameters of structural planes,time-varying characteristics of slurry viscosity.Based on the mass conservation equation of TOUGH2 and the strength reduction method of FLAC3D,the pulsating grouting of fractured rock mass was simulated,the variation of shear strength parameters was obtained according to the interpolation conversion of slurry filling rate,and the influence of grouting pre-reinforcement on slope stability was analyzed to obtain the optimized pre-reinforcement design scheme.The results show that using the pulsating grouting pre-reinforcement scheme of two rows of holes,row spacing of 1.5 m,hole depth of 8. 5m, the slope safety coefficient can reach more than 1.83,so the scheme is not only feasible but also relatively economical.The research method can be used to optimize the design scheme and obtain reasonable design parameters.The research results can be used for reference to similar projects.