The invention discloses a liquid crystal compound and a preparation method thereof, a composition comprising the compound as well as a high-frequency assembly comprising the liquid crystal medium so as to solve the problem in the prior art that the comprehensive performance is low. The structure of the liquid crystal compound is as follows: the formula is as shown in the description. The liquid crystal composition comprises less than or equal to 100 percent of a compound as shown in the formula), 0 to 65 percent of a compound as shown in the formula and 0 to 50 percent of a compound as shown in the formula. The liquid crystal compound has the advantages of low dielectric loss, high quality factor and wide nematic phase temperature interval, and is suitable for the fields of filters, phaseshifters, phased array radars, 5G communication networks and the like. The invention provides a liquid-crystal high-frequency assembly with wide working temperature range, low loss and high tuning rate.