Under the framework of nonlinear quantum field theory,we show the total Hamiltonian operator Htot for the interaction between an electron field and a photon field,and study the contribution of the nonlinear term A2 in the strong laser field.In this paper,we describe electrons with the Schr?dinger quantum wave field of Fermi-Dirac statistics.By applying “self-consistent mean field”,“effective mass” approximation and the displaced harmonic oscillator coherent theory,we derive the Lee-Low-Pines expression f(b+) of electron wave-photon field operator function.Then using the differential formula of f(b+) b+,we derive some relevant calculating formulas,including detailed expressions of electron energy Ek and wave field parameter βw.Furthermore,we also derive self-energy Ek=0 and renormalized mass m of electrons according to these expressions.