The effect of temperature on microstructure and tensile deformation behavior of an Al-16Si-5Fe-1Cu-0.5Mg-0.9Zr (wt%) alloy fabricated by a powder metallurgy processing was investigated in temperature ranges from 673 to 813K under a high strain rate of 1.4x10(-1)s(-1). The elongation increased with increasing temperature up to 793K, and then decreased with further increase in temperature. A superplastic elongation over 300% was achieved in the optimum temperature range of 783-803K owing to the occurrence of grain boundary sliding, a limited grain growth and the formation of an optimum amount of a liquid phase in the vicinity of grain boundary. On the other hand, above the optimum temperature, a rapid grain growth and an excessive amount of a liquid phase were suggested to cause the rapid drop of elongation.