Abstract: Cyclic peptide drugs have gradually become an emerging research direction due to their some favorable properties such as high-efficiency binding affinity, high selectivity, lower toxicity, and stable metabolism. In recent years, the number of cyclic peptide drugs under clinical research has continued to increase. Unlike the previous cyclic peptide drugs, which were mostly derived from natural products and their derivatives, these cyclic peptide drugs are designed by genetically encoded display technologies which are based on rational design and in vitro evolution (such as BT1718, PTG-300, POL6326, etc). Among them, phage display technology has some advantages such as mature research system, low cost, and simpler operation that make it well recognized and praised by the majority of researchers in this field. Here, we reviewed the recent progress of applying phage display technology to explore diverse cyclic peptide libraries, which, we believe, will contribute more valuable candidate cyclic peptide drugs in clinical research.