Disclosed are a dimethylphenylammonium long-chain compound, a preparation, a self-assembled structure and a use thereof. The compound can have an ultra-long-acting anaesthetic effect, is a N-diethylaminoacetyl-2,6-dimethylphenylammonium compound, and the structure thereof is as shown by formula (I). The compound can perform self-assembly in an aqueous solvent to form a micelle or a gel, and the micelle or gel can exert a long-time local anaesthetic effect on an organism, wherein the local anaesthetic and/or analgetic time may exceed 72 hours. The compound can be used as a biological material capable of performing self-assembly in water to form a micelle or gel and having a local anaesthetic effect； at the same time, the compound can also be used as a biological material for wrapping a pharmaceutically active molecule and/or drug carrier, comprising a pharmaceutically active molecule and/or drug carrier used for treating pain, pruritus and other symptoms, as well as a preparation excipient used for a delivery system, etc., all having good prospects.
