A　unified　approach　of　free　vibration　analysis　for　stiffened　cylindrical　shell　with　general　boundary　conditions　is　presented　in　this　paper.　The　vibration　of　stiffened　cylindrical　shell　is　modeled　mathematically　involving　the　first-order　shear　deformation　shell　theory.　The　improved　Fourier　series　is　selected　as　the　admissible　displacement　function　while　the　arbitrary　boundary　conditions　are　simulated　by　adjusting　the　equivalent　spring　stiffness.　The　natural　frequencies　and　modal　shapes　of　the　stiffened　shell　are　obtained　by　solving　the　dynamic　model　with　the　Rayleigh-Ritz　procedure.　Various　numerical　results　of　free　vibration　analysis　for　stiffened　cylindrical　shell　are　obtained,　including　natural　frequencies　and　modes　under　simply　supported,　free,　and　clamped　boundary　conditions.　Moreover,　the　effects　of　stiffener　on　natural　frequencies　are　discussed.　Compared　with　several　state-of-the-art　methods,　the　feasibility　and　validity　of　the　proposed　method　are　verified.