通过对M20 mm的10.9级高强度大六角螺栓楔负载试验中抗拉强度不确定度的来源进行分析，确定了螺栓抗拉强度的影响因素，并对测量结果的不确定度进行评定。结果表明：螺栓楔负载试验过程中抗拉强度不确定度来源主要包括试验力值、螺栓基本中径和小径、拉伸速度和数值修约等；抗拉强度的不确定度报告为R_m=1 114 MPa，U_rel=2%（k=2）。

The uncertainty sources of wedge load test of grade 10. 9 high strength large hexagon bolt with the diameter of 20 mm were analyzed, the influencing factors of bolt tensile strength were identified and the uncertainty of the test results was evaluated. The results show that the main sources of uncertainty of tensile strength in bolt wedge load test included test force value, bolt basic pitch diameter and minor diameter, test speed and rounding off of numerical value. The uncertainty of tensile strength was reported as R_m=1 114 MPa, U_rel=2%(k=2).