Defining an appropriate flight vibration specification is a critical issue at an initial design phase, for optimized design of components in a surface-to-air missile (SAM). As the related document (MIL-STD-810G) doesn’t provide detailed value, appropriate procedures for estimation of flight vibration specification are required for design of a surface-to-air missile. In this study, the method-making appropriate specification without an actual flight test is introduced. Comparison between a theoretical approach using the beam theory and FEA is conducted to attain a natural vibration frequency under thrust force. Transient response analysis using commercial S/W is conducted to establish an envelope curve for flight vibration.