The invention discloses a qualitative and quantitative analysis method of elemental sulfur in light petroleum fractions and light petroleum products, wherein the gas chromatography / mass spectrometry is adopted in the method. In the qualitative method, a scanning mode is adopted to analyze various samples, and the qualitative analysis is performed by utilizing the analysis of the obtained mass spectrum, combining the standard mass spectral library search and comparing with the retention time of an elemental sulfur guide sample. In the quantitative method, the ion monitoring mode is adopted and a standard curve is established to perform quantitative analysis, wherein a sample to be tested does not require pretreatment and can be directly sampled for analysis. The qualitative and quantitative analysis method has the advantages of wide linear range, low detection limit, high precision, wide coverage of samples, no interference in analysis, short analysis time and is simple in operation.