Abstract: The paper introduced the theory of pulsed eddy current(PEC) testing. Based on Finite Element Method software, the distribution of magnetism and eddy current was presented for PEC circular probe. The results showed that the eddy current of flat excited coils could be effective to penetrate inside the metal sample, and it could improve the sensitivity of the testing system of PEC testing. Through the analysis of the eddy current density and the penetrating depth for the different excited frequency, the best excited frequency could be concluded. It will provide the guide of PEC probe design.