To search for an alternative for Nd₂Fe₁₄B, we have studied the electronic structures of R₂M₁₄B compounds, where R stands for rare-earth element and M for Mn, Fe, Co and Ni. By density functional theory (DFT), we discuss the atomic coordination environment and partial density of states (PDOS) in detail, with the emphasis on the interaction between the six kinds of M sites and the R atoms. We systemically calculated the electronic structures of sixty R₂M₁₄B compounds to provide systematic and reliable results for explaining the origination of magnetism, which is important for further development of Nd₂Fe₁₄B based magnet materials.