The type-II spontaneous parametric down conversion is used to prepare the entangled photon pairs. In the Mathematica environment, the properties of frequency entanglement, frequency correlation, quantum interference and the influences of parameters for pulse and crystal on the properties are analyzed. The results show that the continuous optical pumping can be used to obtain the maximum frequency entanglement and interference visibility. When the spectral width of pulsed laser is constant, as the nonlinear crystal thickness increases, the combined two-photon spectra become narrow, the frequency entanglement increases, the indistinguishability decreases, and the interference visibility decreases. In contrast, when the nonlinear crystal thickness is constant, as the spectral width of pulsed laser decreases, the combined two-photon spectra become narrow, the frequency entanglement increases, the indistinguishability increases, and the interference visibility increases. For different parameters of the combined spectral function, a photon pair with frequency anti-correlation, non-correlation and positive correlation can be obtained.