The aluminum oxide membrane containing uniform micro-pores displays well-resolved interference pattern in the reflectance spectrum. Adsorption of molecules onto the surface of the porous layer leads to pronounced shifts of the interference pattern. Basing on the changes of pattern, the microporous aluminum oxide membrane could be used for fabricating a new class of sensor. Our experiments demonstrate that the detective limit of stearic acid in chloroform is 10(-10) mol/L.