The characteristics of the LB films of Schiff base aluminium( Ⅲ ), tris(2-hydroxy-5-nitro N-dodecyl-benzylideneaminato) aluminium ( Ⅲ ) [Al (TA 12) 3], were studied. The surface pres sure-area(r-A) isotherm of Al(TA12)3 in the pure water subphase was investigated. The molec ular area, 0.48 nm2, is one-third of the expected value that indicates the formation of an aggre gate. The Langmuir-Blodgett (LB) films of Al(TA12) 3 were transferred and characterized. The UV-Vis spectra and the AFM image both confirmed that the J-aggregates formed. The polarized UV-Vis spectra indicated that the complex plane had to be oriented with an angle of about 30° to the substrate surface. The IR spectra suggested that the complexation took place between aluminium ions and the oxygen atoms of the ligand rather than the nitrogen atom.