Abstract: The structures of four pigments in plant extract of Carthamus tinctorius L. were analyzed and identified by electro-spray ionization multistage mass spectrometry (ESI-MSⁿ) in the negative mode. The identification of the pigments in plant extract of C. tinctorius was based on the comparison of molecular ions and the fragment ions obtained by ESI-MSⁿ experiments with the data was reported in the literatures. The characteristic ESI-MSⁿ fragmentation pattern of the four pigments was discussed, and found to be a specific and useful tool for the structural identification of pigments from this plant.