Purpose <p>This paper aims to propose a time–frequency combination method to predict steady responses of a multi-freedom nonlinear vibration system with multi-interface connections.</p> Methods <p>Firstly, the non-linear mathematical model of a multi-freedom was established, and a time–frequency combination method was proposed in the solving process, in which the non-linear force was obtained by the time-domain method, and the steady response was acquired through Incremental Harmonic Balance Method (IHBM). Then, the bolted cylindrical shell was selected as an object for the application. Considering the non-linear mechanical properties of the bolt-connection interface, we presented the non-linear dynamic model and solving method in detail. The validity and accuracy were verified.</p> Results <p>This shows the present method can be utilized to obtain steady responses of bolted shells considering the friction behaviors in the bolted joints. The accuracy of the results of vibration response was analyzed through the cases with different reserved harmonic orders in IHBM, and it indicates more harmonic should be considered for getting more accurate results. Also, in the time-domain progress, the friction force and locus figure at the position of the bolt can be observed. Finally, several cases were investigated. These analyses show the proposed method is appropriate to study the dynamics of the multi-freedom nonlinear system as the presented bolted cylindrical shell here.</p>