Abstract: Taking the interlaboratory comparison test of metal plate tensile test at room temperature as an example (tensile test items include tensile strength, specified plastic elongation strength and elongation after fracture), expounded the planning and sample preparation of interlaboratory comparison test, analyzed the test results, and studied the application of median value and standardized interquartile distance method in the evaluation of interlaboratory comparison ability. The results show that taking the median value as the specified value and the standardized interquartile distance as the standard deviation of ability evaluation could reduced the influence of extreme outliers on the specified value and the dispersion of results, and made the statistical analysis results and judgments more in line with the objective reality. This method can be widely used in interlaboratory comparison test.