The purpose of this article is to investigate the effect of magnetic nozzle for disk Magnetohydrodynamics (MHD) accelerator using by Q1D (quasi-1-dimentional) numerical simulation. As results, as constant applied magnetic field of 2T is supplied to the MHD channel and 3, 6, 8 and 10T are supplied to the nozzle, acceleration performance for these cases could not observe the significant difference. However as applied magnetic field of 3, 6, 8 and 10T are supplied to downstream side of the MHD channel and the nozzle, gas velocity for case of 6T was accelerated to 3170m/s and 10T was accelerated to 3040m/s. Because of excessive applied magnetic field induced compression due to joule heating and friction loss.