We describe a simple and effective approach to introduce a functional group into polymer film on a solid surface using reactive polymer LB films. N-dodecylacrylamide copolymers containing terminal amino groups in the side chains as the reactive moiety form a stable monolayer, and the monolayer was transferred onto a solid support to modify the solid surface using the Langmuir-Blodgett method. The transferred coatings were characterized with fluorescence, IR spectroscopies, and X-ray diffraction. The reactivity of the terminal amino group incorporated in the LB films was investigated in detail using fluorescein isothiocyanate (FITC) as a fluorescent probe. The chemical reaction between amino groups in the LB films and FITC in the bulk solution was completed within approximately 30 minutes and the chemical bond formation was confirmed by infrared spectroscopy. Furthermore, the fluorescent image of the multilayers reacted with FITC were observed with fluorescent microscopy. This method is effective for tailoring functional organic ultrathin films on solid substrates.