The objective of this study is to investigate the effects of particle parameters and nozzle base width in aluminum oxide particles laden under expanded jet plume structure and physical features. Computational analysis is carried out from internal axisymmetric contoured nozzle to external near field region when free stream is supersonic to obtain steady two-dimensional dilute particle laden flow using TVD class technique and MacCormack scheme. It is assumed that the particle phase is continuum and particle do not collide each other therefore the mechanism of information transfer is occurred between particle and gas. This mechanism initiate relaxation phenomenon. It has been shown that particle suspension attenuate the strength of shock wave and affect the interaction between shear layer and shock wave. And particle size has also a marked effect on the relaxation zone and position of the regular reflection.