In　this　paper,　models　of　suspension　bridge　with　stiffened　R.C　truss　are　analyzed　by　finite　element　method　with　ANSYS　software.　The　accurate　modeling　method　and　optimum　initial　strain　value　conditions　are　proposed.　It　can　also　be　satisfied　for　project　analysis　precision　requirement.　On　the　basis　of　this,　the　dynamic　property　of　suspension　bridge　with　stiffened　RC　truss　is　calculated　and　the　influence　of　major　structural　parameter　on　dynamic　property　is　analyzed,　and　Sanming　Xiayang　suspension　bridge　test　in　Fujian　Province　has　carried　out　and　the　results　of　which　are　compared　with　those　of　analysis.　The　research　results　are　helpful　for　understanding　the　mechanic　property　of　these　suspension　bridges.