Recent discovery of superconductivity in the Iron-based layered pnictides with transitionrntemperature Tc ranging between 26 and 56K has generated enormous interest inrnthe study of these superconductors. In Iron-based superconductors (Iron-based layeredrnpnictides), superconductivity occurs on doping of either electrons or holes in the FeAsrnlayers. The Iron Fe2+, forms tetrahedron with in the layers. This means that pnictidesrnFermi level is formed by 3dxy, 3dyz, or 3d zx orbitals. Very intriguing property of thesesrnnew compounds is the rather high rnexibility concerning elemental substitution, leading tornseveral families of superconductors, termed '1111', '122','11' and so on, depending on thernchemical composition. In this newly discovered Iron-based layered pnictides like cuprates,rnhas triggered challenge towards understanding the pairing mechanism.rnIn this work we analyze superconductivity of Iron-based superconductor. After reviewingrnthe current nding on this systems, we suggest phonon-exciton combined mechanismrnto give a right order of supercoducting transition temperature Tc's for whole class of Fernbased superconductors