Ti-36Nb-2Ta-3Zr-xO (x=0, 0.1, 0.3, 0.5, wt.%) alloys were prepared by non-consumable arc-melting, and the effects of oxygen contents on microstructure, mechanical properties and damping behaviors of Ti-36Nb-2Ta-3Zr-xO were researched by X-ray diffraction (XRD), universal testing machine and Dynamic Mechanical Analyzer (DMA). The results show that the α″ phase transformation is suppressed by addition of oxygen. The damping behavior of the alloys is the typical Snoek-type relaxation and all Ti-36Nb-2Ta-3Zr-xO alloys show good damping capacities at high temperature. With the increase of oxygen content, the peak capacity of damping increases while the temperature change of the damping peak is not obvious. When the oscillating frequency is 1.0 Hz, the peak capacity of damping increases from 0.0283 (x=0) to 0.0355 (x=0.5), and the damping peak temperature is roughly 230℃.