In order to study the Ti₂AlNb alloy superplastic forming and its performance, the materials with temperature range in 920~960℃ and rate of strain 10^-3~10^-5 s^-1 within the scope of superplasticity are studied. The results show that the material at 960℃, 1×10^-4 s^-1 when the strain rate has a good superplasticity with maximum elongation rate reaching 230% and strain rate sensitivity index 0.31. Marc software was used to simulate the three layers structure of Ti₂AlNb alloy superplasticy forming process, and the formation of defects was analysed. The analysis results show that the 1/3 of the core sheet thickness of the face sheet thickness, can effectively improve the three layers structure of surface defects; Combined with superplastic forming/diffusion bonding process, it realizes Ti₂AlNb alloy the preparation of three layers structure, and improves three layers structure surface defects by changing the core sheet and the thickness of the face sheets. The results show that using reasonable technology and process parameters can achieve the preparation of hollow sandwich structure of the alloy.