miRNAs are a class of noncoding RNA molecules about 18-25 nt in length. As key gene expression regulatory factors, they may inhibit or degrade mRNA by incompletely or completely complement to mRNA. Their abnormal expressions are closely related with the carcinogenesis of prostate cancer (PCa). Some miRNAs trigger cancer, while others inhibit the malignant changes. In this article we summarize the latest information on miRNAs expression prolifing and potential biomarkers,in particular the roles of miRNAs in PCa.