In this research, the effects of Al, S and Al & S atoms doped on the HCN interaction with beryllium oxide nanotube (BeONTs) are investigated by using density functional theory at the cam-B3LYP/6-31G(d) level of theory. Inspection of computational results reveals that the adsorption energies of all considered models are in the range of -1.39 to -31.84 Kcal mol-1 and exothermic in view of thermodynamic approach. Due to doping Al and Al & S atoms, the adsorption energy, and the gap energy of BeONTs/HCN complex alter significantly from the original values, and so the conductivity and activity of the nanotube increase significantly from the original values. The natural bonding orbital (NBO), and molecular electrostic potential (MEP) results demonstrate that the HCN molecule has a donor electron effect. The computational results indicate that doping of Al, S and Al & S increase the sensivity of the BeONTs to detect and adsorb the HCN molecule.