The invention discloses a tension-torsion test specimen fixture, which comprises an upper chuck, a lower chuck and a tension-torsion test specimen, the upper chuck and the lower chuck are respectively provided with upper jaws and lower jaws, an upper clamped section of the tension-torsion test specimen is fixed by the upper jaws of the upper chuck, a lower clamped section of the tension-torsion test specimen is fixed by the lower jaws of the lower chuck, the upper clamped section of the tension-torsion test specimen is provided with upper test specimen key slots, the lower clamped section of the tension-torsion test specimen is provided with lower test specimen key slots, the upper jaws of the upper chuck are provided with upper jaw key slots corresponding to the upper test specimen key slots, the lower jaws of the lower chuck are provided with lower jaw key slots corresponding to the lower test specimen key slots, keys are mounted between the upper test specimen key slots and the upper jaw key slots, and keys are mounted between the lower test specimen key slots and the corresponding lower jaw key slots. The tension-torsion test specimen-clamping effect of the jaws of the tension-torsion test specimen fixture is good, the shapes of the clamped sections of the test specimen are not limited, the structure is simple, clamping does not need mechanical power, mechanical operation noise does not exist, the environment cannot be affected, and both the purchase cost and the use cost are low.