The　Bridge　is　located　in　strong　earthquake　area,　and　with　high　piers,　long　girders　and　single　longitudinal　sloping.　In　order　to　decrease　the　seismic　response　and　construction　cost　as　well　as　easy　erection,　a　lightweight　composite　structure　with　continuous　CFST　truss　girders　and　CFST　composite　piers　is　applied.　To　make　sure　the　mechanical　behavior　reasonable,　referencing　to　the　span　arrangement　of　long　connected　structure　bridges　at　home　and　abroad,　different　aspects　are　researched　including　mechanical　behavior　under　normal　service　loading,　stability,　seismic　performance.