AbstractSpherical Si@Si₃N₄ granules were first prepared by in situ combustion synthesis. The inside of the granules is dense without cracks, and the two phases at the interface are well‐bonded. More significantly, no binder was used between the Si₃N₄ grains on the surface layer, thereby avoiding phonons scattering of metal oxides. In addition, crystallographic orientation relationships between Si and Si₃N₄ were identified by coupling transmission electron microscopy with selected area electron diffraction technology, and much more potential matching planes are also predicted according to the edge‐to‐edge model. It was found that the minimization of the interfacial energy will promote the formation of a transition layer at the interface, leading to the well‐bonded between core and shell. On the basis of the observations, the underlying growth mechanism of the Si@Si₃N₄ was comprehensively analyzed and put forward. Benefiting from the remarkable merits, the as‐synthesized Si@Si₃N₄ granules showed great potential for alternative fillers in solving heat dissipation problems for electronic devices.