Hydroxy acid compound of substituted phenyl ester, preparation method and medical use thereof are provided. The title compound is shown in formula (I), Y═C1-4 straight carbon chain. The compound can release 2,6-diisopropylphenol rapidly under the action of enzymes in vivo, which has sedative, hypnotic and/or anesthetic effect. By protecting the hydroxyl group of 2, 6-diisopropylphenol in compound of formula (I), the first-pass metabolic activity of 2, 6-diisopropylphenol is reduced, so that the synthetic compound can be used for sedation, hypnosis, and/or anesthesia.