This paper investigates the effect of the CBN abrasive types, sizes, concentration, bond amount, and porosity of a vitrified-bonded CBN wheel on grinding ratio, grinding forces, and surface roughness of grinding hardened steels. The experiment results showed that during grinding hardened steels the amount of bond with increase of the depth of cut increased, which makes the wheel to have a better bonding strength to get a better grinding ratio and surface roughness of the workpiece. The grinding forces produced increased with the increase of the depth of cut. In addition, too much porosity of a vitrified CBN wheel will cause the low bond strength, leading the wheel to wear rapidly. Hence, to obtain a higher grinding ratio and better surface roughness of the workpiece during the grinding hardened steels should select relatively a higher amount of bond, a lower porosity, and a higher grit strength and concentration, but the grinding forces produced were relative higher.