Aluminum content and Fe3Al phase in the Fe-Al alloy layer of a new calorized steel were researched by EPMA, X-ray diffractometry (X-RD), TEM, etc. The test results indicate that the Fe-Al alloy layer of the calorized steel is composed of an Fe3Al phase and a-Fe(Al) solid solution. There are no higher aluminum content phases, such as brittle FeAl2, Fe2Al5, and FeAl3. The stable Fe3Al (13.9-20%Al) in the alloy layer of the calorized steel has excellent chemical and mechanical properties. The ability of the calorized steel to resist deformation can be remarkably improved.