The disclosure relates to a liquid crystal compound having a structure of the general formula P2, wherein, R1 represents C1-C6 alkyl, R2 and R3, which are identical or different, independently represent C1-C6 alkyl, and R4 represents C2-C6 alkenyl. The disclosure also relates to a preparation process of the liquid crystal compound, a liquid crystal composition comprising the liquid crystal compound, and a liquid crystal display panel comprising the liquid crystal compound.