Abstract: The eddy current sensor must be designed to meet the requirement of special eddy current testing. A new kind of arc eddy current sensor was proposed in terms of the definite test object. A 3-D accurate electromagnetic model was established with finite element method. The impedance of check-coil was calculated based on the finite element numerical simulation in different cases, such as variable parameters of coil, different excited frequency with flaw or flawless in test workpiece. Finally, the experimental results was presented, and the results from experiment and finite element analysis were in agreement very well by comparison.