Earlier in the 1990s,direct injection of naked mRNA has been proved to be an approach to achieve the exogenous gene expression in vivo.However,the instability and high-immunogenicity of mRNA becomes the main challenges of further development and application of this technology.Recently,with the in-depth research of mRNA structure and the advancement of nucleic acid technologies,chemically synthetic modified message RNA(modRNA)has emerged as a newly-developed gene vector,featuring stability,low-immunogenicity and high expression of target proteins.Based on the related researches,the concept,structure,mechanism and research status of modRNA were concluded,and the advantages and flaws along with the potential improvement direction were put forward in this paper.