Maize is an important crop all over the world,and is a good model for studying shading tolerance.MicroRNAs(miRNAs)are known to play critical roles in plant stress responses,lots of which have been found under environmental stress,but shading-associated miRNAs have not been identified in maize.In this study,an inbred line 502 with shading-sensitive characteristic,was used to reveal miRNAs expression differences between shading and natural light in maize ear at 10d after shading by using high-throughput sequencing technology.The results showed that 130 conserved miRNA belonging to 21 families were identified.Out of them,45 miRNAs were differentially expressed under shading and natural light.In addition,12 novel miRNAs were predicted under natural light and shading.Among 142 shaded-associated miRNAs,94 were up-regulated in shaded condition and 48 down-regulated,and these differentially expressed miRNAs may participate in regulated hormone,flower timing,metabolic and development.These results suggested that maize yield decrease under shading was attributed partly to differences in expression and function of some special miRNAs in maize ear development between shading and natural light.