The changes of the electric match composition at different time simulating accelerated life test were analysed by X-ray diffraction. The conditions of the life test were temperature (60±2) ℃,relative humidity 95％±3％. It was found from the test that when high humidity and high temperature atmosphere exist,the electric match composition would deteriorate easily. Results show that the composition is not changed after the life test proceeds 1.5 days,but the relative peak value of Pb(SCN)₂ become weaken after 3 days. Any of its original material could not be found from X-ray spectrogram after 6 days. The characteristic peaks were observed after 9 days lifetest, like after 6 days life test. Furthermore,PbSO₄ diffraction peak and green material Cr₂O₃ were also found when 9 days.