During　the　recent　construction　activity　in　China,　concrete　filled　steel　tubes　(CFST)　typology　is　innovatively　applied　in　beam　bridges　with　CFST　composite　truss　girders　and　CFST　lattice　piers.　The　subject　is　Ganhaizi　Bridge,　one　of　the　most　unusual　viaducts,　has　a　total　length　of　1811m　and　is　an　experimental　truss　bridge　that　uses　steel　tubes　for　nearly　the　entire　structure.　This　paper　presents　the　study　on　nonlinear　seismic　performance　of　Ganhaizi　Bridge.　Seismic　response　characteristics,　piers　yielding　order　and　internal　force　redistribution　effect　in　plastic　scope　are　investigated　through　a　simplified　fiber　finite　element　model　based　on　the　second　unit　of　this　bridge.　Take　extreme　edge　strain　of　CFST　columns　as　criterion,　the　horizontal　most　adverse　seismic　input　direction　for　this　curved　bridge　is　perpendicular　to　the　bearing　connection　on　both　ends,　the　influence　of　vertical　ground　motion　should　be　simultaneously　considered.　After　turn　into　plastic　stage　with　increasing　peak　ground　acceleration　(PGA),　the　main　stress　direction　of　lattice　piers　and　composite　piers　are　both　in　plane,　axial　forces　increase　less　than　seismic,　while　displacements　increase　greater.　Bending　moments　of　high　piers　increase　greater　than　short　piers,　which　is　expected　to　facilitate　seismic　performance　of　the　whole　bridge.