The low-abundance proteins play an important role in the biological activity of living organisms,involving in many physiological or pathological processes,such as metabolism,transcription and translation.Therefore,the analysis and identification of low-abundance proteins are vital in the study of proteomics.Combinatorial peptide ligand library(CPLL) is an effective method for the enrichment of low-abundance proteins,and the detection and identification of low-abundance proteins could be achieved after treated by CPLL.According to studies on the CPLL reported in recent years,its applications in different fields including the studies on low-abundance proteins in human,animal and plant protein samples were reviewed.The main purpose of this review is to provide a reference for future researches and applications of CPLL.