In this study, a Schiff base called (E)-2-((2-hydroxy -3-methoxy benzylidene)amino)-5methylphenol (L) was used as a ligand. Spectrophotometric properties of the ligand have been defined and the optimum conditions for determining aluminium by complex by UV-Vis. spectrophotometry. The absorbance of Al(III)-L complex obeys Beer's law between 1.4 µg mL -1 and 13.5 µg mL -1 for the aluminium in the optimum conditions. Under optimum conditions, the determination of aluminium in Kompensan® drug was done successfully. The LOD and LOQ values of the developed method were 0.01139 μg mL -1 and 0.0345 μg mL -1 , respectively for the ligand.