Abstract: A method based on a typical kind of excitable media—BZ reaction media is applied to image processing. The kinetics of Tyson model for describing BZ reaction is studied, then a two-dimensional cellular automata according to singular perturbation theory is constructed and applied to image processing. Experiment shows that a series of results such as edge enhancement, grayscale transformation, conversion between positive and negative pattern and so on can be obtained. Moreover, all these results can be got during one evolving process.