Abstract: MicroRNAs (miRNAs) are small endogenous regulatory RNAs composed of approximately 18 nucleotides to 25 nucleotides, and are highly conserved non-coding RNAs, which regulate gene expression in post-transcriptional processing through complete or incomplete combination with the target genes. A strong regulatory factor, miRNA has become a hotspot in tumor research. In recent years, the miRNA-200 family has played important roles in the expression and function of tumors of epithelial origin. For example, the mechanism and targets in tumor cell proliferation, invasion, and metastasis have been investigated. The miRNA-200b is a member of miRNA-200 family. In this article, the latest advances in structural features and mechanism of miRNA-200b and the relationship between miRNA-200b and tumors of epithelial origin were reviewed.