The dielectric properties of compositional disordered perovskite ferroelectrics (1-χ) Pb(Mg1/3Nb2/3) O3-χPbTiO3 (x=0:00, 0.10, 0.20, 0.40) were investigated as a function of temperature and frequency. The non-Debye relaxation of Pb (Mg1/3Nb2/3) O3 was observed clearly around the temperature of the dielectric permittivity maximum (Tm). The frequency dependence of Tm was analyzed using a generalized Arrhenius relationship ω =ω0 exp [2 (T0/Tm) p]. For relaxors with different compositions, a clear change in dynamic behavior can be indicated by the power parameter p, which is related to the growth of interactions between polar microregions. The degree of dielectric relaxation and degeneration of the compositions from relaxor ferroelectrics to normal ferroelectrics can be explained by the interaction of polar microregions.