For electromagnetic scattering of 3-D complex electrically large conducting targets,a new hybrid method MoM-SBR/PO is presented to calculate multi-reflection contribution in the PO region, by introducing SBR method that based on Ray-Density Normalization (RDN). Complex matrix multiplication procedure is avoided in this method. Finally, numerical results are presented and compared with reference MoM2D solutions in order to illustrate accuracy and efficiency of the proposed approach.