This paper dealt with how the aging time and temperature affected the hardness of beryllium bronze layer in the explosive welded beryllium-bronze/carbon-steel composite plate. The properties of shearing, bonding, cold bending and microhardness were studied in term of the composite plate, including the aging and nonaging. The optimum aging treatment process of the composite plate is aging temperature at 320°C for 3 hours. And the results show that: aging treatment has no obvious effects on the shear strength but sharply decreases bond strength of the composite plate. And aging treatment to a certain extent reduce the cold bending prroperty. After aging treatment, the microhardness value and distribution of carbon steel was no obvious change, and the microhardness of beryllium bronze sharply raised and smoothly distributed.