Starting from kinetic equations,we discussed stimulated Raman scattering(SRS)by including both Landau damping(LD) and the collisional damping(CD).It was found that the linear growth rate of SRS is reduced substantially due to LD and CD.SRS can occur only for a region determined by both electron temperature and density .Gap in the spectrum corresponding to Raman scattering can be explained by the p resent model.