This article presents an investigation of dynamical behaviors of perfect and defected FIXED– FIXED single-walled carbon nanotube (SWCNTs) model as a beam structures. The fundamental frequencies and modal participation factors for FIXED– FIXEDsupported SWCTS are considered through this analysis for the first time. Energy-equivalent model is implemented to find a relationship between the energy stored in atomic chemical bonding and potential energy of mechanical beam structure. Nanotube software modeler is exploited to create a geometrical structural of SWCNTs by defining its length of nanotube, bond distance between two atoms, and chiral angle. The tube of SWCNTs are simulated as FIXED– FIXED-supported structure at both ends, while bonding between each two atoms is modeled by 3D beam element with circular cross section. Parametric results are illustrated to display the effects of vacancy on activation and deactivation of vibration modes, fundamental frequencies, and modal participation factors of SWCNTs.