Abstract: This paper introduced the basic principle of eddy current testing, and was using the method to test homemade stainless steel groove. It obtained the impedance diagram for artificial groove and shaking produced signal. Through eddy current testing on 11 stainless steel store tanks, two positions having signal impedance diagram similar with artificial groove impedance diagram were found. The macro inspections verified that 3 surface crack defects existed in the two positions, confirming the feasibility of surface crack testing by eddy current testing of stainless steel weld.