Abstract: In this paper, second-order analysis of tall building tubular structures by use of the Finite Element Method of Lines (FEMOL) is presented. The framed tubes are firsfly replaced by equivalent orthotropic continua. Then the equivalent continua is analyzed by applying FEMOL in which the nodal displacements are taken as primary unknown functions.The Minimum Potential Energy Principle is used to set up the Ordinary Differential Equations (ODE) of second-order analysis. The ODEs are directly treated by ODE Solver, which is a general purpose program developed for solving various ODE. Then the second-order displacement and internal forces are obtained.