A novel inversion method combining the Born iterative method (BIM) with multi-grid technique is developed to solve the nonlinear inverse scattering problem for two-dimensional lossless dielectric inhomogeneties using time-domain scattering data.In the inversion procedure

the size of the discretization grid inside objects is reduced gradually.In the previous inversion procedure

because the condition number and dimension number of the matrix obtained by discretizing the integral equation are relatively small

this method has a good robustness and ability to converge more easily to the true profile.Several examples are given to show that this method reduces vastly computational time of the inversion procedure and can accurately reconstruct the higher-contrast scattering object than that of the BIM.It is more important that this method has the simplicity and can be used to other arbitrary inverse scattering method.