Mechanical alloying process of Al-8wt.% Ni powder was investigated for the various milling time in order to get the steady state powder. High temperature deformation behaviors of the sintered specimens were investigated by activation energy calculated after high temperature compression tests at the strain rates of 2.5$ imes$10-3 s-1, 2.5$ imes$10-2 s-1 and 2.5$ imes$10-1 s-1 at the temperature range between $350^{circ}C$ and $450^{circ}C$. The steady state was obtained after 1000 minutes of milling with the PCA of 1.5 wt.% stearic acid under the condition of grinding media to powder weight ratio of 50 : 1 and impeller rotating speed of 300 rpm. True activation energy of Al-8wt.% Fe alloy was estimated to be 181 kJ/mole at the temperature range of 350~ $400^{circ}C$ and 265 kJ/mole at the range of 400~$450^{circ}C$.