The present disclosure discloses an alkanolamine multi-tailed lipid, a preparation method therefor, and a use thereof. The structural formulas of the lipid such as compound of Formula I, compound of Formula II or their stereoisomers, their tautomers, or their pharmaceutically acceptable salts: The ionizable lipid compound of the present disclosure maintains nanoparticle stability and delivery efficiency while simplifying LNP composition, offering advantages of high efficacy and low toxicity. Even under neutral conditions, the ionizable lipid compound can still adsorb mRNA through hydrogen bonding and van der Waals interactions. The synthesis method for the diethanolamine multi-tailed ionizable lipid of the present disclosure is straightforward. The ionizable lipid can be prepared on a large scale via a few addition reaction steps, which is convenient for high-throughput material screening.