Based　on　the　DQM　(Differential　Quadrature　Method),　the　frequency　equations　and　boundary　conditions　of　curved　girder　are　discretized　respectively.　By　the　choice　of　the　unequal　spacing　form　of　the　sampling　grid　points　and　the　replaced　equation　approach　of　boundary　conditions,　the　out-of-plane　natural　vibration　characteristic　of　the　one-span　circular　curved　girder　and　the　one-span　cyclotron　transition　curved　girder　are　computed　respectively.　Through　a　comparison　with　the　exact　solutions,　the　high　effectiveness　of　DQM　is　verified　and　the　influence　of　grid　point　quantity　on　the　solving　precision　is　discussed.　Based　on　the　solution　of　natural　vibration　characteristic　of　curved　girder,　the　influences　of　stiffness　ratio　of　bending　and　torsion,　warping　coefficient　and　boundary　constraint　form　on　natural　vibration　frequency　of　curved　girder　are　studied　respectively　and　the　parameter　influence　laws　of　circular　curved　girder　and　cyclotron　transition　curved　girder　are　compared.　The　research　shows　that　the　natural　vibration　characteristic　of　curved　girder　can　be　computed　conveniently　and　efficiently　by　the　DQM　and　the　stiffness　ratio　of　bending　and　torsion,　warping　coefficient　and　boundary　constraint　form　have　obvious　influence　on　the　vibration　frequency　of　curved　girder.　The　computation　results　show　that　the　fundamental　frequencies　of　the　two　types　of　curved　girders　are　both　reduced　with　the　decrease　of　boundary　constraint　conditions　and　the　parameter　influence　laws　are　similar　in　most　boundary　constraint　conditions;　however,　the　parameter　influence　of　the　cantilever　type　cyclotron　transition　curved　girder　reflects　a　reversed　law　compared　to　the　most　boundary　constraint　conditions.