Abstract:In a system of quark matter we study the chiral phase transition, the behavior of the chiral and quark number susceptibility and the CEP at nite temperature and chemical potential. This is done within the framework of two-avor Nambu and Jona-Lasinio model. We have calculated the chiral quark condensate and the quark number density and, with this, we have found the phase transition type. With these quantities we have determined the phase diagram for QCD and the CEP.