Disclosed is a liquid crystal compound. The compound has a general structural formula as shown by formula I. Such a compound has good thermal and UV stability, large positive dielectric anisotropy Δ∈, and can achieve a low threshold voltage when used in optics, thereby having great significance to the fast response of display devices, and therefore being very suitable for formulating a liquid crystal mixture. A liquid crystal mixture containing such a liquid crystal unit can be applied to various display devices, and is especially suitable for TN-TFT and STN display devices, but can also be used in IPS (in-plane switching) and VA (vertically aligned) display devices.