The　nonlinear　vibration　of　the　telescopic　cantilever　composite　plate　subjected　to　the　in-plane　excitation　and　the　third-order　aerodynamic　force　is　studied　when　it　is　in　the　deployment　and　retraction.　Based　on　classical　laminated　plate　theory　and　Hamilton　principle,　the　nonlinear　partial　differential　equation　of　the　telescopic　cantilever　plate　in　the　process　of　deployment　and　retraction　is　established.　Then,　the　Galerkin　method　is　used　to　discrete　the　nonlinear　partial　differential　equation　into　the　ordinary　differential　equation　with　time-varying　coefficients.　Frequency　variation　diagrams,　time　history　diagrams　and　phase　diagrams　are　obtained　by　numerical　methods.　The　influence　of　axial　velocity,　width-to-thickness　ratio　on　the　nonlinear　dynamic　characteristics　of　the　telescopic　cantilever　composite　plate　is　discussed.　The　results　show　that　the　larger　the　axial　moving　speed　is,　the　more　likely　it　is　to　cause　the　amplitude　to　diverge　when　the　telescopic　cantilever　plate　is　deploying　at　a　uniform　speed.　However,　amplitude　divergence　does　not　occur　in　the　retracting　process.　©　2023　Journal　of　Dynamics　and　Control.　All　rights　reserved.