Fourier transform transmission infrared and UV-Vis absorption spectra have been measured for a photochromic behavior of a novel amphiphile 2,4-dihydroxy-N-octadecylbenzylideneamine bearing Schiff base moiety as polar head in the close-packing LB films on solid supports. Measurement of π-A isotherm show that 2,4-dihydroxy-N-octadecylbenzylideneamine formed a stable and condensed monolayer at air-water interface. The built-up multilayer was found to exhibit photochromic behavior upon irradiation of 365nm light. The configuration rearrangement of the π-electrons induced a large spectral change.