Abstract: A modified generalized differential quadrature (MGDQ) method is utilized to investigate the coupling vibration and buckling characteristics of functionally graded material (FGM) beams with even porosity distribution in thermal environment and under the action of an initial axial mechanical force. Various types of temperature distributions are considered through the thickness direction, and the material properties are temperature-dependent according to modified Voigt mixture power-law model with porosity. Using an n-th order generalized beam theory (GBT), the free vibration and buckling governing equations for this system are derived by Hamiltonian principle as a unity. The control parameters for three different boundary conditions are proposed, and the MGDQ method can be utilized to solve the coupling vibration response with MATLAB computational procedure. Based on the duality between the static and dynamic behaviors of the structure, the buckling responses are obtained by writing loop subprogram, which can greatly simplify decoupling process and improve calculation efficiency. The effects of various beam theories, boundary conditions, different types of temperature rise, initial axial force, thermal-mechanical loads, porosity, material graded index and slenderness ratios on the vibration and buckling behaviors of FGM beams are discussed, and the significant duality for the two different mechanical behaviors of the structure are also revealed by several numerical examples.