A novel Ti-0.5Nb-0.5Si (in wt.%) alloy is oxidized at 650∼850 °C for 100 h in air, which shows a significant higher oxidation resistance than pure Ti. The advantage of the alloy becomes more obvious with increasing temperature. At 850 °C for 100 h, mass gain of the alloy only accounts for 12.7% of that of the pure Ti. A key reason is the formation of a Ti2N layer coherent with Ti matrix. The oxide scale of the alloy with less porosity and alleviated stratification creates an environment at the scale/substrate interface favorable for the formation of Ti2N.