The ground states of lattice properties, formation energy and magnetizations of R2Fe14B (R: rare-earth element) were calculated by the first-principles method based on the generalized gradient approximation (PAW-GGA). GGA+U method was applied to deal with local magnetic moments from 4f shell of rare-earth elements. Magnetic moments were calculated with and without spin-orbital interactions (SOI). Site occupation of Dy ions in Nd2Fe14B lattice is studied by partial substitution of Dy for Nd on different lattice sites. Calculated substitution energy indicates that the Dy2Fe14B is more stable than Nd2Fe14B and the Dy ions prefer to occupy the 4f sites in Nd2Fe14B lattice. It is also found that rare-earth ions occupying the 4f sites will interact more strongly with Fe ions and thus show a greater impact on the local magnetization of Fe. The interaction between rare-earth ions and Fe ions is positively correlated with distance.