Post-translational modification of proteins plays a very important role in regulating function, activity and positioning of proteins, as well as the progression of cell cycle and cell differentiation. SUMOylation (SUMO, small ubiquitin-like modifier) is a highly dynamic process which can be reserved by SUMO specific proteases (SENPs) family. SENPs can catalyze and remove SUMO from SUMO-connecting target proteins, as well as from their precursor proteins. Furthermore, some members of this family are involved in the maturation and activation of SUMO. Thus, deSUMOylation is as important as SUMOylation to the regulation of function and activity of SUMO-connecting proteins. This paper reviews the structure and biological characteristics of SENPs family.