Based on the nonlinear dynamics model of inextensional beam on elastic foundation,the primary resonance of the beam subjected to harmonic excitation was investigated. Through the method of multiple scales,the frequency-response equation and the second-order approximate solution of the primary resonance of the beam were obtained. Then,by means of the frequency-response curve,the effects of foundation model,Winkler parameter,excitation amplitude and boundary condition on the primary resonance of the beam were...