In this paper, the theory of Fourier optics and diffracted scattering are used to analysis the effect of diffracted scattering of particles A12O3 in real rocket exhausted jet on the moire deflectogram. The phenomenon of moire fringes confusion caused by the diffracted scattering of particles A12O3 is studied experimentally. The results show that for the solid propellant of containg Al powder of 3-8%, the flow field of its rocket exhausted jet can be visualized with moire deflectometry.