The microstructure change of Mo70-Cu sheet rolled at room temperature in different deformation degrees and the effect of different annealing temperatures on its plasticity was studied. The results show that the main deformation mechanisms of Mo70-Cu sheet rolled at room temperature are the sliding deformation of Cu and Mo and the twinning deformation of Mo and its plasticity can be recovered with uniform microstructure after annealed at 1000-1100 ºC for 1 h.