Titanium alloys with gradient microstructures have broad prospects for aerospace applications due to their excellent comprehensive properties. In this study, Ti2AlNb-based alloy samples with gradient misrostructures were obtained by gradient extrusion at 980°C. The gradient microstructures of Ti2AlNb-based alloy samples were characterized by XRD, SEM and TEM, and its properties were studied by nanoindentation and nano-scratch tests. The influence of gradient microstructures on the properties of Ti2AlNb-based alloy was deeply investigated. The results show that the microstructure in the core of the gradient extruded Ti2AlNb-based alloy specimen is mainly composed of the coarser B2 phase and the near-equiaxed α2 phase distributed at the grain boundaries, and the dislocation density is low, which is mainly distributed in the B2 phase and the B2/α2 phase boundaries. The microstructure in the edge is composed of smaller B2 phases, a large number of rod/slat-like O phases and a small number of equiaxed α2/O (rim O) phases, and the dislocation density is high, which is mainly distributed at the interface between the slat/equiaxed O phase and the B2 phase, and in the O phase and α2 phase. The core of the gradient extruded specimen has the lower hardness and better plasticity. The edge has higher hardness under various effects such as O-phase strengthening, fine-grained strengthening and dislocation strengthening, and the wear resistance are significantly improved. The gradient microstructure can make the Ti2AlNb-based alloy obtain good comprehensive service performance. This study provides theoretical and experimental basis for promoting the application of Ti2AlNb-based alloy gradient materials in aerospace.