Current paper systematizes the work devoted to the application of the aromatic spin probe EPR spectroscopy for the study of heterogeneous alumina catalysts, as well as supplemented by new researches carried out in IHP SB RAS. The advances of the method and the mechanism of probe molecules interaction with active surface sites and their nature are considered. There are noted some contradictions in views on mechanisms, nevertheless the modern point of view tends to participate BAS in the ionization of aromatic probe molecules.