The first and second order differential dielectric spectra have been first presented to seperate various polarizations of material conveniently and definitelly in the time domain measurement. The polarization response function introduced traditionaly as the form of exp(-(t/τ)α) can be deter-mined by the differential spectral curve. The experiments show that there are two typical differential spectral curves corresponding to τ=1 and τ-1/2. The number of the polarization mechanisms, the individual mechanism contribution to the total polarization and its response time τ can be derived from the number, the height and the location of peaks of the differential spectral curves. The seper-ability of the differential spectral curves indicates that there is no reason for the conventional assump-tion that τ has some distribution function while a is a constant. The measurements on paraffin sam-ple demonstrate the slow polarization informations about the motions of the localized segment and the whole of a molecular chain in the process of the paraffin melting. The experiments also give the re-sult that the response time τ increases exponentially with temperature which is in contradistinction from the temperature dependence of relaxation time followed from frequency domain measurement.