The　load-carrying　capacity　assessment　of　existing　bridges　is　associated　with　the　bridge　condition　evaluation,　maintenance,　management,　repairing　and　strengthening.　It　has　become　of　increasing　importance　for　both　bridge　design　engineers　and　construction　owners.　In　this　paper,　the　differences　between　the　design　and　assessment　of　bridges　are　addressed　and　the　assessment　methods　in　the　specifications　of　China　and　America　are　compared.　First,　the　statics-based　assessment　methods　are　discussed.　Then,　a　dynamic-based　assessment　procedure　is　proposed,　which　involves　both　field　ambient　vibration　testing　and　finite　element　analysis　and　updating.　Two　typical　existing　bridges　are　used　as　the　case　studies　to　simulate　the　process　of　evaluation.　Finally,　further　research　needs　in　the　load-carrying　capacity　assessment　of　existing　bridges　are　presented.