An ultrathin film from polyaniline derivative (PAAA) and diazoresin photosensitive polymer (DR) was fabricated layer-by-layer (LBL) with a self-assembly technique. The micropatterns were achieved on LBL ultrathin film after UV exposure through a photomask. To directly characterize the patterned image, a fluorescent-labeled IgG was incorporated into the film, and a fair clear fluorescence image of the micropattern was achieved using laser confocal fluorescence microscopy. The controllable pattern of fluorescent-labeled IgG on a silicon surface may provide a simple and fast method for the immunoassay, and the conductivity of PAAA/DR film makes it possible to combine the electronics with the immunoassay.