Ferrous aluminides are one of the most important substitution materials for super alloys. In this case, FeAl intermetallic compound has very specific applications in strategic situations. Solid synthesis method is usually used for the production of this compound, which has low formation kinetic rate. However, using mechanical ball milling process before heat treatment process is caused the formation rate to be increased dramatically. So, the main purpose of this work is investigating the effect of applying mechanical and thermal activating factors, on the formation of FeAl compound, by using high temperature ball milling. In this investigation, pure Fe and Al powders were mixed by the stoichiometric ratio in the range of the formation of FeAl compound. This mixture was ball milled with the ball to powder ratio of 20/1 in Argon atmosphere. At first, after optimizing the milling parameters, the powder mixtures were hot milled at 700 and 800 °C (in the range of Fe and Al melting point) for times ranging from 3 to 9 hr. In this temperature, the reactant phase (Al) is in molten phase and Fe phase in the solid state. In order to investigating the effect of temperature and time, EDX, SEM, and XRD tests were conducted on the powder mixtures. At second stage, the powder mixture was finally tested by DTA test (heating rate of 10 °C/min, Argon atmosphere), isothermal test (at 700 °C, Argon atmosphere), and SHS (on the cylindrical compacted powder specimens), in order to study the formation mechanism of the compound. Results showed that the homogenous (single phase) FeAl intermetallic compound is achieved by 6 h milling of Fe-Al powder mixture (molar ratio of Fe/Al =1) at 800 °C. Moreover, results showed that the formation mechanism of this compound involves two main stages. The first stage includes the reaction of liquid Al and solid Fe, and the formation of Fe2Al5 intermetallic compound. Second stage includes the diffusion of Fe and Al to the Fe2Al5 compound and the formation of FeAl intermetallic compound. Finally, it's concluded that the diffusion process is the most important controlling factor in the rate of formation of FeAl compound after primitive reaction. Key Words Iron Aluminides, Intermetallic, Solid-Liquid Reaction, Hot milling, Synthesis Isfahan