The effects of Cr, Mo or B additions were investigated on B2↔DO₃structural transition temperature (T_c) and mechanical properties of Fe-28at.%Al. The raw materials were arc-melted in vacuum and then subjected to the following heat-treatments to maximize the DO₃ordered structure : 1000℃/7days, slowly cooled to 500℃ and then held for 5 days. In the effect on the grain refinment, the addition of alloying element B was the most effective. The addition of Cr or Mo had little effect. When 1at.%Mo was added, T_c increase about 30℃, but Cr had a very little effect on T_c. On the contrary, when B was added, T_c was apt to come down minutely. In the additional effect of alloying element on the mechanical properties, Cr was apt to decrease the microvickers hardness and yield strength, Mo and B didn`t have much effect. In the case of compressure strength test, the effect of the environment on the yield strength was contrary to the result of the tensile strength test.