Abstract: In order to understand the mass spectral characteristics of dimethyl dimethylpyrophosphonodithionate, synthesis sample including dimethyl dimethylpyrophosphonodithionate was analyzed by gas chromatography-mass spectrometry (GC/MS) and tandem mass spectrometry (MS/MS). The spectra of ten chemicals in synthesis sample were obtained by GC/MS in full-scan mode of electron impact (EI) and chemical ionization (CI). According to isotopic abundances in CI spectra, elemental compositions of chemicals were deduced. Among of them， six chemicals structures were identified by comparing EI spectra with library spectra. Then the dimethyl dimethylpyrophosphonodithionate and four unknown chemicals were analyzed by MS/MS. Through the analysis of different cleavage fragments of these chemicals, mass spectrometric fragmentation pathways were discussed and unknown chemicals structures were deduced. Ten chemicals were identification in synthesis chemicals, and the spectra characteristic of different chemicals were conclusion, which could provide reference for analysis and identification of this kind of compounds.