This article makes a deep study on layer potential developed in reference[l]. The curves that describe the relation between U and e1ectron density N⁰_e，and the relation between Cu-O plane number 1 and U，are traced. Furthermore，this article studies the micromechanism of layer potential-effective Hamiltonian for Cu-O layer，Effective Hamiltonian for Cu-O layer is obtained. The condition for holes (slave-fermions) to be condensed to Cooper pairs is dicussed.