Abstract: The feasibility of preparing flake absorbent by self-reactive spray forming technology and the effect of substrate on microstructure and electromagnetic properties of flake absorbent were studied. Fe+MnO₂+Fe₂O₃+ZnO was treated as the reactive system. Substrates made of graphite, tungsten copper and brass materials were chosen to prepare the flake Mn-Zn ferrite absorbent based on mechanism of self-reactive spray forming technology. XRD and SEM were used to characterize the morphology phase and microstructure of the absorbent. The electromagnetic properties of the flake absorbent were tested by the web vector analyzers. The results show that, flake Mn-Zn ferrite absorbent can only be obviously acquired by brass substrate, and the absorption intensity and bandwidth of the absorbent prepared on brass is better than the other two kinds. It means that the choice of substrate has a great effect on both microstructure aspect and electromagnetic properties aspect of flake absorbent prepared by self-reactive spray forming technology.