This　paper　investigates　the　dynamic　responses　of　clamped-clamped　functionally　graded　material　circular　cylindrical　shell　at　both　ends　with　small　initial　geometric　imperfection　and　subjected　to　complex　loads.　The　small　initial　geometric　imperfection　of　the　cylindrical　shell　is　characterized　with　the　shape　of　hyperbolic　function.　The　effects　of　radial　harmonic　excitation　combined　with　thermal　loads　are　considered.　The　classical　theory　and　von-Karman　type　nonlinear　geometric　equation　are　applied　to　obtain　partial　differential　equation　of　the　functionally　gradient　material　circular　cylindrical　shell　by　the　Hamilton＇s　principle.　The　partial　differential　dynamic　equations　are　truncated　by　the　Galerkin　technique,　using　the　modal　expansion　with　the　inclusion　of　axisymmetric　and　asymmetric　modes.　The　effective　material　properties　vary　in　the　radial　direction　following　a　power-law　distribution　accordancewith　the　volume　fractions.　The　effects　of　volume　fraction　indexes,　ratios　of　thickness-radius　and　length-radius　on　the　first　three　dimensionless　natural　frequencies　of　the　perfect　cylindrical　shell　and　its　counterpart　with　imperfection　are　given.　The　effects　of　radial　external　loads,　initial　geometric　imperfections　and　volume　fraction　index　on　the　nonlinear　dynamic　response　of　the　clamped-clamped　FGM　circular　cylindrical　shell　are　discussed　by　numerical　calculation.