A novel method of preparing polymer-supported colloidal palladium catalysts, a otic-step preparation method (OSPM), is reported. Polymer-supported colloidal metal catalysts were synthesized directly from monomers and metallic precursor in one step. X-Ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), infrared (IR), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and photomicroscopy were applied to characterize the structures of the polymer catalysts and the distribution and dispersion of metal in the polymer. The influence of the synthetic conditions on the synthesis and structures of the catalysts was studied. OSPM gives a new method to prepare polymer-supported colloidal metal catalysts and is a far shorter process than the traditional preparation methods. The experimental results show that colloidal palladium particles in the polymer were ultrafine, highly dispersed and distributed uniformly.