Abstract: Based on quasi-static test results, fiber element models using OpenSees software were established to investigate the effects of major factors on the horizontal load-displacement skeleton curve of a uniform sectional CFST lattice column with flat laced tubes. Then a tri-linear model was proposed to simulate the load-displacement skeleton curve, and the simplified calculation methods of related control parameters of the model were also put forward through theoretical derivation and statistics analysis, including the elastic stiffness calculation formula considering the shear deformation of CFST limbs and lacing tubes; the horizontal peak load calculation formula based on a virtual work principle and the correlation curves between axial force and bending moment; the simplified calculation method of the peak displacement and ultimate displacement for which the displacement ductility factors obtained by statistical data can be selected flexibly according to the actual requirements. Compared with the results of quasi-static tests, FEM parameter analysis, and extended parameter analysis for actual structural size, the tri-linear model can effectively simulate the skeleton curve of such structures, and the simplified calculation formulas for related control parameters of a skeleton curve have high accuracy.