Embedded system has become more and more popular in image processing, spatial computing and other fields. In order to achieve a balance in three major aspects of power consumption, cost and computing power, it is an effective solution to improve the computing ability of embedded system, using the multi-core and multi processor system based on parallel computing method. This paper discusses the basic structure of embedded multi processor system based on Cortex, and has a research on parallel image median filtering algorithm on this system. Experimental results show that the parallel algorithm can improve the performance of image median filtering exponentially on the embedded multi processor platform.