Photonic crystal fiber (PCF) has excellent features compared with the traditional optical fiber, especially nonlinear effect and birefringence effect. By quoting Lorentzian model of Raman gain spectra in PCF, the gain spectra are studied under the action of Raman scattering together with parametric amplification, when the pump wave polarization is oriented at 45° between the axes. The result shows that the input power and the group velocity mismatching have a great influence on the gain spectra because of the interaction between parametric amplification and Raman scattering. The gain spectrum bandwidth widened and the intensity enhanced as the input power and the group-velocity mismatching enlarged. Stokes-wave is multiple-peaked structure when input power is greater and stable in anomalous dispersion regime .The Stokes-waves gain are greater than anti-Stokes waves gain in normal dispersion regime. The pump wave can be changed into pulse array under certain conditions so that the T-frequency pluses can be extracted from it.