To explore the effect of persistent slip bands (PSBs) formed during cyclic loading on the static mechanical behavior of materials, [1‾12]-oriented Cu single crystals are selected as target materials, and the tensile behavior of Cu single crystals prefatigued to the stress saturation stage at different plastic shear strain amplitudes (γpl) and the corresponding microstructures, surface deformation features and fracture morphologies are systematically studied. The results show that the formation of few soft PSB ladder-like structures in hard dislocation veins during prefatigue deformation at γpl = 3.7 × 10−4 below the plateau region of cyclic stress-strain (CSS) curve can promote a synchronous improvement of strength and ductility (SISD) compared with the unfatigued crystal. As γpl increases to a lower value of 9.0 × 10−4 within the plateau region, the strength and ductility reduce sharply compared with the case at γpl = 3.7 × 10−4 due to more concentrated plastic deformation caused by a high volume fraction of prefatigue-induced PSBs. With continuously increasing γpl to a higher value of 2.3 × 10−3 within the plateau region, non-uniform dislocation distribution in labyrinth structures and the short spacing between labyrinth walls as well as the fine dislocation cells formed during tension jointly give rise to a slight increase in strength and ductility compared with the crystal prefatigued at γpl = 9.0 × 10−4. As γpl is increased to the level beyond the plateau region, the ductility and ultimate tensile strength continuously increase, resulting from the co-existence of wider deformation bands and dense dislocation walls.