Two types of Fe13Cr5AlxY with x=0, 0.3 (wt%) alloys, denoted as 0Y and 0.3Y, respectively, were prepared in a vacuum non-consumable arc furnace and exposed in 1000 and 1200 ℃ steam for 2 h. The high temperature oxidation behavior of the alloys was studied by thermogravimetric analyzer with steam generator. The microstructure and composition of the oxide film before and after oxidation were analyzed by XRD, FIB/SEM, EDS, and TEM. Results show that the addition of Y can refine the grains of FeCrAl alloys and form the spherical or elliptical hcp-Al₃Fe₁₄Y₂ second phase. The oxidation kinetics of the Fe13Cr5AlxY (x=0, 0.3, wt%) alloys oxidized in 1000 and 1200 ℃ steam for 2 h follows a parabolic growth law. The addition of Y can decrease the oxidation mass gain rate of the alloys. The oxide film of the two alloys is mainly composed of α-Al₂O₃ and a small amount of Fe oxide exists on the outside of oxide film. The second phase in the oxide film of 0.3Y alloy is oxidized into YAlO₃, Fe₂O₃ and Fe(Cr, Al)₂O₄. The ridged oxide film is formed on the surface of 0Y alloy. The oxide film of the alloy peels off from the substrate under oxidation at 1200 ℃. The oxide film on 0.3Y alloy is smooth and has good adhesion to the matrix. Therefore, the formation of the ridged oxide film is inhibited by adding Y, which can reduce the oxidation mass gain rate and enhance the high-temperature steam oxidation resistance of the alloy.