Environmental barrier coating (EBC) is a surface protection layer established between the service environment and the engine material to prevent or reduce the environmental erosion of the engine. Mullite is regarded as an important material for environmental barrier coating due to its good high temperature resistance, chemical compatibility， oxidation resistance and thermal conductivity. The preparation process of nanostructured mullite feedstock was studied, and the purpose was to prepare nanostructured feedstock with good sphericity, smooth surface, good fluidity and high density. This paper uses nano Al₂O₃ and nano SiO₂ as raw materials, and uses spray drying and solid phase sintering methods to prepare nanostructured mullite feedstock. The microstructure and morphology of feedstock at different heat treatment temperatures were studied by means of X-ray diffractometer and scanning electron microscopy. The experimental results show that the sphericity of solid-phase sintering at 1300 ℃ + 150 min is consistent with the sphericity of the feedstock obtained by spray drying, and the surface is relatively smooth, with fewer defects, the particle size of the feedstock is about 60 μm, and the grain is nano structure.