Abstract: In order to learn more about the ethyl herbicide residues, we selected six commonly used herbicides as study. These six sulfonylurea herbicides, including bensulfuron-methyl, chlorsulfuron-methyl，pyrazosulfuron-methyl, metsulfuron-methyl, tribenuron-methyl and thifensulfuronmethyl were analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), equipped with gallium gun (⁶⁹Ga), both their positive and negative ion spectra were obtained clearly. The data show that quasi-molecular ions and recognizable fragment ions are present in the spectra. The main large fragment ions come from cleavage of C—N bond of the group of acid amide in their structure, according to their fragmentation pathways we discussed. The summing-up we discussed mostly based on the stability of chemical bonds and molecular weight of combined fracture fragments. In conclusion, TOF-SIMS is expected to qualitatively determine sulfonylurea herbicides as well as their derivatives with high sensitivity and high speed. It can provide a theoretical basis for the analysis of sulfonylurea herbicide and their residues.