Abstract: The present invention provides a mRNA composition for microneedle administration and its application. The composition includes an aqueous phase solution and a lipid solution, wherein the lipid solution encapsulates the substance in the aqueous phase solution to form lipid nanoparticles (LNPs), and the aqueous phase solution includes mRNA encoding the corresponding protein and a buffer. It was found that an improved buffer pH could substantially increase the drug loading capacity of LNPs, and reduce the use level of composition and excipients and the dose for microneedle administration with less toxic side effects and better therapeutic effects, and the microneedle administration technology could achieve increased effective expression, decreased expression in the liver, and prolonged in vivo expression of mRNA composition, and increased antibody titer in response to low-dose mRNA in vivo. The present invention really realizes microneedle intradermal administration of mRNA composition.