Abstract: The highly nonlinearity and non-uniqueness of the geoelectric model constrain the application of simulated annealing method in the Time-domain ElectroMagnetic (TEM) explorations. A simulating annealing inversion method is presented to get the geoelectric model from the data of the TEM method. Firstly, by the dual digital filtering method, the fast and accurate forward problem is settled. Furthermore, the inversion is converted into an optimization issue and the simulating annealing inversion method is applied to the search for the global optimal solution, of which the search step can be adjusted adaptively, hence improving the searching effeciency. The comparison results with conventional inversion methods show that the proposed method can achieve the global optimal solution and a more accurate result of the geoelectric model.