Al2O3 dispersion strengthened copper composite (Al2O3 Cu composite) was produced by internal oxidation. The hardness and electrical conductivity of the produced Al2O3 Cu composite (0.60 wt.% Al2O3) subjected to high temperature annealing treatments after different cold work deformations have been investigated; the microstructures of the composite have also been analyzed by TEM. Results show that the microstructure of the composite is characterized by an uniform distribution of nano-Al2O3 particles in Cu-matrix; the composite can maintain more than 91% hardness retention after 1h, 1000 degrees C annealing treatment; the recrystallization of the Cu-matrix can be largely retarded and only partially happened even annealing for 1h at 1050 degrees C, following cold deformation of 84%.