Abstract: According to GB/T 228.1—2021, conducted tensile tests on magnesium alloys and evaluated the uncertainty of the results. The results show that within the range with a probability of 95%, the tensile strength of magnesium alloy was (343±6) MPa, with a composite standard uncertainty of 2.95 N/mm², degrees of freedom of 35, and a coverage factor of 2.03. The specified plastic elongation strength of magnesium alloy was (236±10) MPa, with a synthetic standard uncertainty of 4.53 N/mm², a degree of freedom of 28, and a coverage factor of 2.05. The elongation after fracture of magnesium alloy was (6.0±1.0)%, with a synthetic standard uncertainty of 0.510%, a degree of freedom of 24, and a inclusion factor of 2.06.