Cu58.1Zr35.9Al6 bulk metallic glass bars with a diameter of 3 mm were prepared by copper mould suction casting. The effects of temperature on the elastic property and microstructure of the alloy were studied. The results show that the changes of the elastic property and microstructure can be divided into three stages corresponding to different temperature regions. Below the glass transition temperature Tg, the structural relaxation occurred. In the temperature range from Troom to 150 ℃, the structure transition is local and short-range, so the elastic properties only change slightly. However, in the temperature range from 150 ℃ to Tg, because the intermediate-range and long-range atomic diffusion take place with aggregation and rearranging under the sufficient condition, the excess free volume is removed, and thus the elastic properties are improved greatly with the increase of temperature. Within the super-cool liquid regions, from Tg to the onset crystallization temperature Tx, the new phase Cu10Zr7 forms while the elastic properties decrease a little near Tg (490 ℃). Above Tx, the elastic properties increase further with increasing of temperature, and the small amount of Cu8Zr3 phases form besides a large amount of Cu10Zr7. The temperature has a considerable effect on the elastic property and microstructure of Cu58.1Zr35.9Al6 bulk metallic glasses. The effect is closely related to the large decrease of the free volume, the improvement of the atom order degree and the formation of separation phases.