Abstract: The principle and applications of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) were briefly introduced. The characteristics and scope of the application of matrixes were summarized. Three Schiff base nickel complexes were respectively analyzed by MALDI-TOF-MS. The results showed that the molecular weight M+H⁺ peak and the isotopic abundance were very consistent with the theoretical value. By this method not only the molecular weight of Schiff base complexes was accurately determined, providing important assistance for the structural identification, but also it would be an effective and rapid tool for identification of metal organic complexes, and supplemented by Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS) for confirmation.