In　this　paper,　the　new　functionally　graded　three-phase　composite　cylindrical　shell　is　assumed　as　a　common　structure　in　the　carrier　rocket　in　the　future,　and　we　creatively　study　the　nonlinear　forced　vibration　of　this　cylindrical　shell　considering　the　interaction　of　different　factors　in　the　complex　operating　environment,　including　the　aerodynamic　forces,　external　excitations,　and　hygrothermal　environment.　Based　on　the　first-order　shear　deformation　theory,　Von-Karman　geometric　nonlinear　theory,　and　Hamilton＇s　principle,　we　derive　the　nonlinear　partial　differential　equations　of　motion　of　the　functionally　graded　three-phase　composite　cylindrical　shell.　Considering　the　axisymmetry　of　the　perfect　circular　shell,　there　is　a　1:1　internal　resonance　between　the　conjugate　modes　of　this　cylindrical　shell.　On　this　basis,　the　nonlinear　forced　vibration　of　the　cylindrical　shell　is　investigated　by　a　combination　of　Galerkin＇s　method　and　the　pseudo-arc　length　continuation　method.　Matcont　toolbox　can　directly　solve　the　ordinary　differential　equations　to　obtain　the　nonlinear　frequency　response　curves.　The　method　can　effectively　obtain　both　stable　and　unstable　solutions,　avoiding　the　mathematical　difficulties　encountered　in　the　formulation　process,　and　facilitating　the　study　of　the　effects　of　parametric　variables　on　the　resonance　response　in　complex　environments.　The　results　show　that　the　variation　of　material　parameters　and　the　complex　environment　have　important　effects　on　the　nonlinear　resonance　response　of　functionally　graded　three-phase　composite　cylindrical　shell.