Electromagnetic tomography has potential value in process measurement. The frontier of electromagnetic tomography system is the sensor array. Owing to the excited signal acting on the sensor array directly, the excited strategy and the frequency and amplitude of the signal affect the quality of the information that the detected coil acquired from the object space. Furthermore, it would affect the accuracy of the information post extracted from the object field. To improve the sensitivity of the sensor array on the changes of the object field distribution, upgrade the sensitivity and accuracy of the system and guarantee high precision and high stability of the experimental data, use the finite element simulation software COMSOL Multiphysics to analyze the excited strategy and the characteristic of the excitation frequency of electromagnetic tomography. Establish the foundation in optimal using of electromagnetic tomography system.