Abstract: The causes of uncertainty in the measurement of torsional property of metal wires were introduced, and the torsional property of metal wire on a 70E steel wire were tested. The mathematical model of the torsion property test of metal wire was established, and the calculation formula of measurement uncertainty was given to calculate the measurement uncertainty of the torsion property test of metal wire. The results show that the possibility of the measured value of the torsion property of the metal wire of the 70E steel wire falling within 34.5-5.99, 34.5+5.99 was 95%.