Based　on　the　theory　of　virtual　work　and　principle　of　thermal　elasticity,　exact　solutions　for　in-plane　displacements　of　curved　beams　with　pinned-pinned　ends　are　derived　explicitly.　In　the　case　of　infinite　limit　of　radius,　these　equations　coincide　with　that　of　the　straight　beams.　Compared　with　the　results　of　FEM,　the　analytical　solutions　by　the　proposed　formulae　are　accurate.　Basing　on　the　stiffness　matrix　of　statically　indeterminate　curved　beams　at　three　freedom　direction,　the　dynamic　characteristics　are　derived　explicitly.　The　analytic　method　of　dynamic　characteristics　for　curved　beam　performed　in　this　paper　would　provide　a　scientific　base　for　further　study　and　design　of　the　curved　bridges.