Many theories beyond the standard model predict the existence of a new massive neutral gauge boson called Z’. In this seminar, I will discuss the discovery and identification of such a Z’ with the ATLAS detector in the e+e- channel. First, I will review the different studied theoretical Z’ models coming from Grand Unified Theories and Extra-dimension scenarios. In a second part, I will show, using realistic detector parameterization, that the ATLAS discovery potential is very optimistic. Finally, I will discuss how to infer the underlying theory from a hoped Z’ discovery.