In this paper, a novel method for solving an inverse problem of electromagnetic tomography is given and a reconstruction algorithm is proposed. Firstly, the simplified sensing model is derived on the basis of a reasonable assumption about media layer in the sensor system. By using a Green’s function method, the solution of the electromagnetic equations of the simplified model which can be classified as a Fredholm equation is achieved. A perturbation method is used to solve the ill-posed equations. The feasibility of using the proposed simplified sensing model and image reconstruction algorithm is shown using reconstruction results.