In order to investigate the criterion for the nucleation of persistent slip bands (PSBs) near a ∑3(111) coherent twin boundary, where is a preferential site for formation of PSBs, a high-cycle fatigue test is carried out at room temperature using a copper bicrystal specimen with the twin boundary. PSBs are observed near the boundary in the connection with the evolution of extrusion! intrusion on the specimen surface. The slip behavior is different from that predicted by the Schmid factor. A finite element method (FEM) analysis is conducted for the bicrystal, and it reveals that the increase of resolved shear stress on the specific slip system due to the constraint of deformation between the crystals is the main cause for promoting the nucleation of PSBs near the twin boundary. By taking into account the interaction between the primary and the secondary slip systems, it is possible to specify the nucleation behavior of PSBs near the twin boundary.