Neurospora crassa is the model organism for research on small RNA in fungi.The regulatory mechanisms on small RNAs vary accordingly with evolution of species.The latest progresses of the regulatory mechanisms on fungi small RNA and their core components are summarized,which will achieve a further comprehension of the evolution of species.Recently,more and more new small RNAs have been discovered as a result of the development of regulation mechanisms of small RNAs,which can exploit a new research field and orientation for the study of RNA interference.