In order to study the microstructure of face center cubic metals induced by thermo-mechanical impact, molecular dynamics method was used to investigate the dislocation evolution of monocrystalline copper treated by warm laser peening (WLP). The effects of plastic strain on the dislocation development were researched through centrosymmetry parameter. Moreover, the effects of temperature on the dislocation development induced by plastic strain during WLP were also investigated. Finally, the strengthening effects of WLP were analyzed by work hardening. It is shown that partial dislocation and stacking faults are induced by plastic strain in the way of“vacancy group-partial dislocation-stacking faults”. As the plastic strain increases, the amount of stacking faults and their stacking extent increases, which leads to a better effect of WLP in work hardening. A higher temperature can promote the nucleation and development of dislocations induced by WLP. The hardening effect of WLP increases with the temperature within 200 ℃, and the hardening effect reduces while it increases to 250 ℃ because of the dislocation annihilation.