Electromagnetic tomography is one kind of electrical impedance tomography which develops faster in recent years. The relation map between electromagnetic field and measuring electric potential provides adequate prior information and consequently is crucial to image reconstruction of electromagnetic tomography (EMT). Firstly the forward problem of EMT is studied in this paper and a new 2-D model of eight homogenous coils is set up in simulative software named COMSOL Multiphysics, finite element method (FEM) is practiced in the solution of forward problem. The simulation on characters of object position, conductivity, and permeability in sensing field is carried out and seriously analyzed. The relation between conductivity of materials and detective electric potential are discussed, revealing that material distribution is mainly presented in the real part of the electric potential. The investigation on object field of EMT is beneficial not only to future reconstruction work but also to optimum design of sensor system.