Abstract: It is quite important to evaluate measurement uncertainty during the precious metal testing.However, evaluation and application of uncertainty in most domestic precious metal testing lab are immature nowadays.In this paper, the measurement uncertainty was evaluated by determination the percentage of Pd in Pt950 jewelry by means of inductively-coupled plasma atomic emission spectrometry (ICP-AES).The authors established a mathematic model, and analyzed various factors.The result showed that the expanded uncertainty was calculated to be 44.02 ‰±0.326 8 ‰ finally.The uncertainty mainly came from the standard solution preparation and measurement of calibration curve which resulted in uncertainty of 0.003 4,and from the sample repeatability tests resulted in uncertainty of 0.001 3,and the influence of mass and volume were very small.This study not only aims at improving the reliability and integrity of the test results, but also aims at providing references for the improvement of the uncertainty evaluation program in domestic gem and metal testing lab by giving an illustrative demonstration.