A high gradient of displacement field occurs when a yield line is formed in a plate with elasto-plastic material. For such applications, the extended finite element method has shown to be an effective numerical method to capture the behavior of a plate with a locally nonsmooth displacement field, and a displacement field with a high gradient. In this article, a six-node isoparametric plate element with extended finite element method formulation is presented to capture the elasto-plastic behavior of a plate in small-deformation analyses. The Hermite function is adopted at the element level to enrich both the translational and the rotational displacement approximation fields so that nonsmoothness in displacement fields near a yield line can be simulated. Copyright © 2013 John Wiley & Sons, Ltd.