Nb-22Si-20Ti-6Mo-xTa (x = 0, 1, 2, 3, 4 at.%) alloys with different content of Ta were prepared by vacuum non-consumable arc melting method, and effects of Ta content on phase constitution, microstructure and mechanical properties of Nb-22Si-20Ti-6Mo-xTa alloys were investigated. Results show that addition of Ta does not change the phase composition Nb-22Si-20Ti-6Mo-xTa alloys. All alloys are consisted of Nbss and β-Nb5Si3, Ta is mainly dissolved in Nbss. Microstructure of alloys consisted of bulk primary β-Nb5Si3 phase and Nbss/β-Nb5Si3 eutectic. Addition of Ta refined microstructure, and grain size of primary β-Nb5Si3 phase decreased from 26.84 μm to 14.65 μm. In addition, the amount of primary phase are decreased with increasing of Ta, the amount of eutectic structure are increased. Room-temperature compressive strength of Nb-22Si-20Ti-6Mo-xTa alloys was improved with increasing of Ta content, and it is increased from 2261MPa to 2321 MPa with increasing content of Ta from 0 to 4at.%. Fracture strain of Nb-22Si-20Ti-6Mo-xTa alloys first decrease and then increase with increasing of Ta content. Fracture strain of NST-0Ta alloy is 9.9%, that of NST-1Ta alloy is 9.7%, and that of NST-4Ta alloy increases to a maximum of 10.6%. Compressive strength improvement of alloys is contributed to solid solution strengthening and grain refinement strengthening by addition of Ta. Due to refinement of alloy microstructure and the increase of eutectic structure,fracture strain of alloy is increased.