The effect of substituent on the aromaticity of phosphazene has been investigated theoretically by the application of density functional theory at the level of B3LYP/6-31+G(d,p) method. Phosphazene is isoelectronic with benzene, pyridine or other 6π systems. However, appearance of three phosphorus together with three electronegative nitrogens leads to a non-aromatic ring. Therefore, substituents may have potential to enhance the aromaticity of the parent structure. Both electron donating and electron withdrawing substituents have been replaced with the hydrogens on phosphorus. Nucleus-independent chemical shift (NICS) data have been considered to determine the aromaticity of the systems.