Abstract: Diamond composites are widely used in processing, drilling and other fields, and improving the bonding strength of the diamond skeleton is an important research direction. In this work, Co₅₀Ni₄₀Fe₁₀ multi-element alloy-carbide was used as the binder instead of Co to prepare diamond composites under high temperature and high pressure, and the influence of multi-element alloys and carbides on the microstructure of composites was studied by experiments and thermodynamic calculations. The results show that, compared with Co, Co₅₀Ni₄₀Fe₁₀ multi-element alloy has stronger ability to promote the migration and diffusion of C atoms, which can accelerate the formation of diamond skeleton. Under the condition of high temperature and high pressure, the carbon content in WC increased slightly, which has little effect on the formation of diamond skeleton; TiC lost C slightly, which can promote the formation of diamond skeleton to a certain extent; The C produced by Cr₃C₂ decomposition can promote the formation of diamond skeleton.