The performance of YVO4 crystal as Raman amplifier is reported. The beam quality of Raman Stokes light is improved due to Raman “cleanup” in the amplification stage. Then, by changing the pump pulse width, the experiment is carried out in three different pulse width conditions. The experimental results show that the wider the pump pulse is, the more easily the pump-seed delay is adjusted. By changing the incident angle between seed and pump light, its influence on the performance of Raman amplifier is also studied. Raman amplifier based on four wave mixing (FWM) is very sensitive to the change of the incident angle. Third order Stokes and third order anti-Stokes Raman lights are obtained at different incident angles, and the spectral composition of all the Raman Stokes is identified to the calculated Raman Stokes spectral composition.