The effect of ZnO/Na 2O molar ratio（ Z ）on the properties of Li 2O -K 2O -SiO 2 -Al 2O 3 -B 2O 3 system vitrified bonds and cBN grinding wheels were studied with TG -DSC, X -ray diffraction analysis, scanning electron microscopy and thermal expansion coefficient tests. The results showed that the lower inflation crystalline phase（Li 2OAl 2O 37.5 SiO 2）appeared in the vitrified bond. And by increasing the ratio of Z , all the vitrified bonds' topographic crystal temperature, softening temperature, crystal quantity and density increased while the crystal size was reduced. When the wheel formula was fixed, the porosity of wheel decreased by increasing the ratio of Z while the bulk density, hardness and bending strength all increased. But G -ratio（dry -rubbing QT400）increased at the beginning, and then became lower. When the ratio of Z was 0.75, the values of vitrified bonds' expansion coefficient and softening temperature were 6.902 9×10 -6 K -1 and 805 ℃, respectively. Meanwhile, the bending strength, the porosity and G -ratio of cBN grinding wheel were 73.97 MPa，15.65% and 156.42%, respectively.