Disclosed in the present invention are a cationic compound, a preparation method therefor and a use thereof. Provided by the present invention is a compound represented by formula I having a novel structure, or a pharmaceutically acceptable salt thereof, or a stereoisomer thereof, or a solvate thereof, or a prodrug thereof, or a metabolite thereof, the compound having a fast acting time, and having a long-acting local anesthetic effect after a single administration, wherein the time for which the sensory nerves are blocked is longer than the time for which the motor nerves are blocked； the compound has both a long-acting local anesthetic effect and a selective local anesthetic effect, significantly reducing the side effects of QX314 and QX314 compositions as well as cationic compounds having surfactant structural features, and being more safe； which is to say that the compound represented by formula I of the present invention and the pharmaceutically acceptable salt thereof may be used for the preparation of a safe drug having a long-acting local anesthetic effect and a selective local anesthetic effect, having the advantages of a long-acting local anesthetic effect, good local anesthetic selectivity, reduced nerve damage and greater safety.La présente invention concerne un composé cationique, son procédé de préparation et son utilisation. La présente invention concerne un composé représenté par la formule I ayant une nouvelle structure, ou un sel pharmaceutiquement acceptable, ou un stéréoisomère, ou un solvate, ou un promédicament, ou un métabolite de celui-ci, le composé ayant un temps d'action rapide, et ayant un effet anesthésique local à action prolongée après une seule administration, le temps pour lequel les nerfs sensoriels étant bloqués est plus long que le temps pour lequel les nerfs moteurs sont bloqués ； le composé a à la fois un effet anesthésique local à action prolongée et un effet anesthésique local sélectif, réduisant de manière significative les e
