This invention relates to liquid crystal compound of formula I containing benzene derivatives group that hydrogen substituted by deuterium. Liquid crystal compounds of formula I have not only large positive dielectric anisotropy, but also moderate optical anisotropy and driving voltage, thereby having great significance to formulate a liquid crystal mixture. A liquid crystal mixture containing such type of liquid crystal compounds can be applied in various display devices, which is particularly suitable for TN and STN display devices, and can also be used in IPS and VA display devices.