The effect of the concentration of silane coupling agent KH560 on the dispersion and placement stability of the vitrified bond was investigated， together with the mechanism of modification. Furthermore， cBN grinding tools were prepared with vitrified bond of different dispersion， and the influence of modification methods of vitrified bond and storage time on the micro-mechanism， mechanical properties and grinding performance of cBN grinding tools were studied. The results show that when the KH560 addition was 3.0%， the vitrified bond powder displayed the best dispersion and placement stabilization. The microstructure of CBN abrasive tools prepared by using 3.0%KH560 modified vitrified bond powder for 360 h was uniform， and the bending strength and Rockwell hardness reached the maximum values of 189.3 MPa and 100.15 HRB， which were 12.72% and 5.82% higher than those of unmodified cBN grinding tools respectively. The surface roughness value of the workpiece was 0.054 μm when using this grinding tool to honed the inner holed of bearing steel， which was 48.6% lower than that of the workpiece processed by unmodified cBN grinding tools.