The microwave absorption properties of Ti2O3 were systematically investigated.Experimental results indicate that Ti2O3 has microwave absorption performance with a minimum reflection loss value of-37.6 dB at 18.6 GHz and an effective absorption bandwidth(RL＜-10 dB)of 2 GHz.Further,vacancy defects were introduced into Ti2O3 by carbothermal reduction.Interestingly,the effective absorption bandwidth of Ti2O3 with vacancy defects reach 3.2 GHz.First-principles calculations provide evidence that vacancy defects result in the changes of electric dipole state,leading to a wider effective absorption bandwidth.These results have significance in understanding the origin of electromagnetic phenomena and developing electromagnetic wave absorption materials.