Pseudogenes, disabled copies of functional genes, are structurally similar to its parantal genes, but lost their ability to produce proteins. Pseudogene was used to be considered as a typical kind of non-coding “junk DNA”. Increasing investigations, however, have shown that pseudogenes play important roles in gene regulation and genome evolution. The progress of research on pseudogenes is summarized in light of the origin and sequence characteristics of pseudogenes, identification of pseudogenes, genomic distribution, behaviour of its molecular evolution and functioning.