Anti-reverse cap analog (ARCA)-capped mRNA synthesis kit includes all the critical reagents for in vitro transcription to generate high yields of high-quality mRNA efficiently. This kit could incorporate an ARCA into the transcript. ARCA is incorporated into mRNA exclusively in the correct orientation, generating capped mRNA that is more efficiently translated. The advantages of the ARCA-capped mRNA synthesis kit are that ultra-high-quality components and ARCA-based capping in correct orientation can ensure the integrity and high translation efficiency of mRNA. mRNAs synthesized with the ARCA-capped mRNA synthesis kit can be used for microinjection, cell transfection, in vitro translation, and RNA vaccines.