The invention discloses a 2-methyl-1,3-dioxepane derivative. The structural general formula of the compound is as shown in the formula I. The compound is stable in structure, has a wide liquid crystal state temperature range, good low-temperature intersolubility and large dielectric anisotropy delta epsilon, can be used for realizing a low threshold voltage and low rotary viscosity gamma 1 when being used in an optical device, can be used for improving the performances of a liquid crystal composition material and a display device, and has great significance in quick response of the display device. A liquid crystal composition containing the compound can be applied to preparation of liquid crystal display devices with low driving voltage, wide temperature range and quick response speed. The formula I is as shown in the specification.