Preparation of an antibody-colloidal gold probe (conjugate) specific to aflatoxin B1 (AFB1) and its use in developing a rapid AFB1 diagnostic method was presented in this paper. Monodispersional nanogold colloid was synthesized and preparation of nanogold-labeled polyclonal antibody probe to aflatoxin B1 under friendly and optimal condition. Combination of antibody with nanogold particles was also characterized by UV-visible (UV-vis) light absorption spectra, transmission electron microscopy (TEM), fluorescence spectroscopy, titers, cross reactivity and stability measurements. Furthermore, nanogold-labeled probe was used to develop an immunochromatographic (IC) method for aflatoxin B1 analysis. With this method, analysis could be completed in less than 10 min. Detection time was reduced 6-10 times comparative with ELISA. With visual observation, lower test limit was found to be around 2.5 ng/ml aflatoxin B1 standard solution, which was increased to two times of ELISA.