A new method has recently developed,the solution sampling method(SMM),to quantify the binary rubber blends of NR/BR by pyrolysis/gas chromatography/mass spectrometry(PY/GC/MS).The rubbers were swelled in the cyclohexane,using the hydrogen peroxide solution to destroy the cross-linked structure of the rubbers and then the rubbers can be sloved in the cyclohexane.The rubber solution was applied to the spiral section of the injector.The solvent was evaporated depositing the rubber on the spiral section,and the rubber was prolyzed at 550℃.Then calculate the weight percentage by the characteristic peak area ratio.One test rubber,NR/BR where the weight percentage of NR is 50% was calculated.The error was 5.64%.