With micro diamond powder and silica sol as raw materials，the diamond and vitrified grinding wheel were prepared by sol-gel in-situ method.The effect of dispersant and defoamer on the properties of mixed slurry and abrasives was studied.The results show that with 0.4% naphthalene based super plasticizer added，the dispersity and the fluidity of mixed slurry are good，and the viscosity reaches the minimum value.When the addition of silicone defoamer DD is 0.2%，the microstructure of the composite sintered body is uniform with the minimum porosity and the maximum bend strength.Compared with the grinding wheel without additives，the microstructure of grinding wheel with dispersant and defoamer is dense and uniform.The surface quality of cemented carbide grinded by the new designed wheel is better.No deep scratches were observed，and the surface roughness was 0.04 μm.