Abstract: The fracture of Fe-25Cr-5Al alloy has been studied.Above 1000℃, grains of the alloy grow quickly.When grain size(d)increases to 80 μm,the fracturs mode transited from dimple pattern to quasi-cleavage fracture;d ≥ 100μm,fracture surface appeares cleavage fracture.During thermal cycling treatment process,due to non-equilibrium segregation of chromium to grain boundaries,precpitation of micrometer scale of α'-phases can occur at grain boundaries the formation of σ-phase can result in intergranular fracture.