Regional spectral model (RSM) at National Centers for Environmental Prediction (NCEP) is a primitive equation model and being operationally used for short-range ensemble forecast at NCEP. The RSM uses the same model physics as NCEP global forecast system (GFS) model, which has been significantly updated recently. The current parallel version of the RSM is based on 1-dimensional decomposition using massage passing interface (MPI) and has a limitation in number of processors to use (limited by vertical resolution) and high-resolution simulation. In this study, we present the recent development of fully parallelized RSM-MPI code based on 2-dimensional decomposition on the IBM-SP, distributed-memory parallel supercomputer. Compared to the current operational RSM-MPI code, the new code is about twice faster, can run much higher resolution simulation (about factor of five), and has almost no limitation in number of processors to use (actually limited by a product of both resolutions in horizontal directions that is usually much larger than that of vertical resolution).