Cordycepin, a nucleoside derivative, was extracted from $Cordyceps$ $sinensis$, and then proved to be a bioactive compound present in traditional Chinese medicine Cordyceps. Early investigations revealed cordycepin possessed anti-microbial activity mainly by inhibiting nucleic acid synthesis. Although cordycepin is not used as antibacterial agents in clinic, its other pharmacological effects and possible mechanisms have gradually been deeply studied. This review serves to summarize the research progress of cordycepin.