microRNAs(miRNAs)是一类长度为21~24nt的非编码小RNA，通过与靶mRNAs的3′UTR结合在转录后水平上沉默基因表达，参与多种生理、生化、病理过程。目前有许多研究表明miRNAs影响动物的昼夜节律。论文就miRNAs在昼夜节律中的调控机制进行综述，揭示其在昼夜节律系统中的重要作用，为更深入理解动物昼夜节律系统提供理论参考和研究思路。

microRNAs (miRNAs) are 21to 24nucleotidelong noncoding RNAs and silence gene expression in posttranscriptional level by binding to the 3′untranslated regions (UTRs) of target mRNAs in physiological，biochemical and pathological processes. Many recent research indicated that miRNAs affected circadian rhythm of animals. This review aimed to summarize the regulatory mechanism of miRNAs in circadian rhythm and their important roles in circadian system, so as to provide basis and information in detecting animal circadian rhythm.