Abstract: The effective grouting area for rock bedded slope is calculated.A numerical calculation model is founded by the method of fast Lagrangian analysis of continua three dimensions(FLAC3D).The grouting is done in the effective grouting area.The comparison analysis for the stress field and displacement field before and after grouting are conducted.The analysis results show that after grouting the shear resistance strength and shear stiffness are increased.The stress field and displacement field of rock mass are more symmetrical and continuous.The tensile stress area is reduced gradually.The phenomenon of displacement mutation is reduced,which is good to the stability of slope.