A finite element analysis model of variable cross-sectional concrete-filled steel tubular(CFST)laced column with flat lacing tubes is built with universal program of OpenSEES, and the calculating results of specimen obtained by OpenSEES agree well with the quasi-static test results.The seismic performance of four-element variable cross-sectional CFST laced columns with flat lacing tubes is researched with calculation parameter of column slope, including the rules on energy dissipation capacity, skeleton curve, structure ductility, and stiffness degradation of elements, and these calculation results are compared with the research results of uniform cross-sectional CFST laced columns. And the influence of axial compression ratio, column height (slenderness ratio), vertical spacing of flat lacing tubes, steel ratio of longitudinal element, diameter ratio of lacing tubes to longitudinal tubes, yield strength of steel, concrete strength and other structural parameters on seismic performance of variable cross-sectional CFST laced columns with flat lacing tubes are investigated. It's hoped that the results can provide reference for the improvement of CFST calcalation theory and engineering application of variable cross-sectional CFST laced column piers.