Abstract: Integral equation method is one of effective methods of numerical simulation and inversion calculation for multi-dimensional electromagnetic response.Based on the linearization of the scattering electromagnetic integral equation, conductance imaging using iterative Born approximation is effective.Aiming at the characteristics that iterative Born approximation inversion depends on the initial model and that QL approximation doesn't need initial value, the two step method,iterative QL-Born approximation method,is put forward,which takes the result of QL inversion as the initial model of the iterative Born approximation method and avoids contrived initialization.The iterative QL-Born approximation method is effective and testified by numerical experiments

Key words: integral method, QL approximation, Born approximation, iterative QL-Born approximation