Bimetallic　NPs　with　core-shell　structure　have　aroused　general　concern　because　of　their　unique　atom　arrangement　and　extraordinary　properties,　therefore　shows　great　application　potentials,　especially　in　the　field　of　catalysis.　We　have　reviewed　the　researches　on　synthesis　and　application　of　nanoalloys　and　bimetallic　NPs　with　core-shell　structure　reported　in　recent　years.　In　the　first,　basic　concepts　and　structures　of　nanoalloys　are　introduced,　then　according　to　different　strategies　of　forming　core-shell　structure,　two　main　preparation　methods　are　illustrated,　namely　successive　reduction　and　co-reduction,　which　also　includes　different　systems　like　aqueous,　polyol,　surface　replacement,　dendrimer　complexing　and　epitaxial　growth.　Finally,　the　research　progresses　and　prospects　of　core-shell　nanoalloys　in　catalysis　are　contemplated.　The　problems　to　be　solved　and　future　development　are　also　described.