High-temperature superconductor mechanism and the prediction of superconducting properties such as the critical temperature or superconducting energy gap are among important challenges in quantum theory. These superconducting properties depend on the electron-phonon coupling parameters. Cooper pairs have major role in the appearance of superconductivity, which are created by help of the electron-phonon interaction. More precisely, in conventional Superconductors below the critical temperature electron pairing is the result of the interaction between the Coulomb repulsion and the attraction of electron and phonon, hence the dominance of attraction causes electron-electron interaction. Cuprates are high-temperature and unconventional superconductors, which are mainly of type II superconductors. These are fundamentally strongly correlated electron systems, which are being studied by the Hubbard models and DMFT or DFT methods. Structure of cuprates is a layered structure, in which each layer having a different role in appearance of superconductivity. Some features of conventional superconductors are predicted by BCS theory. This theory can be obtained by applying a set of approximations to the Fr?hlich Hamiltonian, and we are only able to describe the problem in weak coupling regim. An alternative theory is presented by Eliashberg. Eliasberg theory is based on a set of equations by ignoring the approximations and limitations of the BSC theory. In this research, in the first chapter by begin by the Fr?hlich Hamiltonian and applying BCS limitation we will interduced BCS theory. In the next step, by using the electron-phonon Fr?hlich Hamiltonian, we achieve a set of Eliashberg standard equations that we used to obtain features for cuprates. Finally, we study Bismuth base and Lanthanum base cuprates, and analytical approaches, we calculate the electron-phonon spectral function or Eliasberg function as one of the important parameters of electron-phonon coupling for these cuprates, and consequently, using a set of approximations, we study as energy Gap and critical temperature. Prediction of superconducting properties such as the critical temperature or superconducting energy gap are one of utstanding challenges in quantum theory. These superconducting properties depend on the electron-phonon coupling paramets (EPC parametrs). Cooper pair as the effective factor in the appearance of superconductivity is created by the electron-phonon interaction, more precisely, in conventional Superconductors below the critical temperature electron pairing is the result of the interaction between the coulomb repulsio and the atractive electron-phono and the dominance of atraction. cuprates, as one of the High-Temprature and unconventional superconductors, which mostly of type II superconductores, have an important influence on the development of superconductivity. These superconductors are usually studied by using Hubbard Hamiltonian and either DMFT or DFT methodes. Cuprates have a layered structure, in which each layer having a different role in appearance of superconductivity. Some features of conventional superconductors are predicted by BCS theory. This theory can be obtained by applying a set of approximations to the Fr?hlich Hamiltonian, and only are able to describe weak coupling superconductors. An alternative to this theory is presented by Eliashberg. In Eliasberg theory a set of equations by ignoring the approximations and limitations of the BSC theory. In this thesis, in the first chapter by studying the Fr?hlich Hamiltonian and by applying BCS limitation we interduce BCS theory. In the next step, with the help of the electron-phonon Fr?hlich Hamiltonian , we achieve a set of Eliashberg standard equations that we used for obtain cuprates features .Finally, we study Bismuth base and Lanthanum base cuprates, and with the aid of the two analytical approaches, we calculate the electron-phonon Spectral function or Eliasberg function as one of the important parameter of electron-phonon couplingarameterfor these cuprates, and consequently, using a set of approximations, we study features of superconductors such as energy Gap and critical temprature.