Abstract: In order to improve the accuracy of test results,the measurement uncertainty of benzene and its five homologues(toluene,ethylbenzene,p-xylene,m-xylene,o-xylene) in water-based adhesive by GC/MS was analyzed and evaluated via establishing rational mathematical models and analyzing the main sources of uncertainty in this measuring method.The results showed that the expanded uncertainty values of the six analytes ranged from 0.006 to 0.019 mg/kg(k=2).On the basis of the weights of various components of uncertainty,the five selected experimental factors in the order of their influence on determination results were ambient temperature>repeated measure>standing time>apparatus measuring>curve fitting.