Abstract: The existence of residual stress in a component will seriously affect its rigidity and the strength. If the total stress, which superimposes the residual stress with the external working stress, exceeds the material strength limit, it may lead to failure of the component. This paper summarizes the research progress of residual stress testing with nondestructive testing method. Based upon the theory of eddy current thermography (ECT), an approach to detect residual stress of conductive material part has been proposed by using ECT. The theoretical basis of the prposed method is introduced and a scheme of the experiment system is suggested. The impact residual stress in steel samples has been detected by using the proposed method and experiment system. The results show that ECT could be a potential approach to detect residual stress in conductive materials fast and effectively.