Density functional theory (DFT) calculations have been performed to investigate the properties of the electronic structures of pyrazine-doped boron nitride nanotubes (PD-BNNTs). e structural forms were �rstly optimized and then nuclear magnetic resonance (NMR) parameters have been calculated on the optimized structures. e chemical shielding isotropic (CS I) and chemical shielding anisotropic (CS A) parameters were calculated at the sites of 11 B and 15 N nuclei in structural forms of BNNT including the perfect (a) model and PD-BNNTs (b), (c), and (d) models. e results indicated that the changes are most signi�cant for those nuclei placed in the nearest neighborhood of the pyrazine-doped ring. e changes of the electronic sites of the N atoms are also more signi�cant than those of the B atoms. e di�erence of LUMO-HOMO gap for the perfect model was larger than the PD-BNNTs models. Also the atomic charge distribution of N and B atoms has been determined in nanotubes by natural bond orbital (NBO) analysis. All calculations were performed by the B3LYP method and 6-311G * * basis set using Gaussian 98 package of program.