Abstract: 13 kinds 1,2,4,5tetrasubstituted imidazoles(including 5 new compounds, which is compound 2, 3, 5, 6, 7) were characterized from TOF mass spectra obtained under chemical impact conditions (CI-TOFMS) using accurate mass measurements. Fragment ion were obtained and the cleavage ruler was presumed using ESI tandem ion trap mass spectrometry.