A numerical design on the triangular photonic crystal fiber (PCF) based backward multi-pump Raman amplifier is presented. It is demonstrated that high flat Raman gain can be reached based on PCF. Influences of different geometric parameters and germanium doping concentrations on the Raman net gain, amplified spontaneous emission (ASE) noise and double Rayleigh backscattering (DRBS) of the signal have been analyzed. For optimizing crystal fiber Raman amplifier (FRA), there is tradeoff between the geometric parameter and germanium doping concentration of triangular PCF. The results show that PCF is an appropriate candidate for high gain Raman amplifiers.