Abstract: The basic principle of the incremental method in mass spectrometry and itsapplication to quantitative analysis of tungsten oxide are presented in this paper.With this method the standard sample is not required, the accuracy and sensitivityof analysis can be improved. In our work the molding method of powder sampleelectrode has also been improved, here the contamination from molding can beavoided, the auxiliary conductive powder mixed with sample is not necessary.