Abstract: The neutron diffraction data of Nd 2Fe 14 BN x is preliminarily fitted. By using of the results and a small FORTRAN program, the distances of arbitrary coordinates to every atom in the structure are calculated, and so the possible sites of N atoms in the structure, for distances thinking just, are determined. After every possibility is fitted and studied by trail and error method, the N atoms are finally found to enter the interstitial sites 4e(0,0,0.099 0) and 4f(0.097 2, 0.097 2, 0) of the tetragonal structure. The magnetic structure is also studied.