Aim To analyze the fragmentation patterns of diquaternary dipiperaziniumscontaining dithiocarboxyl groups. Methods Positive ion electrospray ionization mass spectrometry inconjunction with tandem mass spectrometry (ESI-MS^n) was used. Results The fragment ion [M^(2+) Cl^-]^+ showed characteristic double peaks with high intensity instead of the parent molecular ionbeing detected. And [M^(2+) - CH_3^+ ]^+ ion had relatively low intensity. Meanwhile, [M^(2+) Cl^- -Cl^- - PhCH_2^+ ]^+ species had the highest intensity as the base peak, which was originated from[M^(2+) Cl^- ]^+, The detailed fragmentation mechanisms are supported with the tandem massspectrometry.