Stimulated Raman scattering is one of the main restriction for the improvement of high power fiber laser. The Raman effect in high power fiber laser is studied through numerical simulation. The results show that SRS can be suppressed effectively by increasing signal wavelength and reducing reflectivity. Also,the Raman characteristics with different pump modes are discussed. For the first time,the Raman effect in high power fiber laser under multi-point pump is studied. The conclusion is useful for the optimizatin of high power double-clad fiber laser.