By using 3/2-D particle simulation code, the stimulated Raman scattering (SRS) in planar and hohlraum targets is studied. Evaluations of linear growth rate of scattering electromagnetic waves and Langmuir waves and nonlinear saturation are obtained in detail. Other results such as electron distribution function, electron temperature and the fraction of super hot-electrons produced by SRS are also given. The density distribution in the underdense coronal plasma region is determined by the analysis of SRS spectrum. These theoretical results are in agreement with experimental observations from the Shenguang-12 Nd-glass laser facility.