Noise in imaging systems comes from all aspects.Noise reduction is an important part of image processing.Median Filter is one of the common methods of noise suppression.The traditional median filter algorithm can reduce the noise but it also leads to the problem of detail fuzzy.According to traditional median filter algorithm,a new algorithm is proposed.At first,the median is compared with the neighborhood.Secondly,it is judged whether the median is in the range of the neighborhood.Thirdly,the value of the center pixel is set according to the result.The new algorithm not only reduces random noise but also protects the details of image to some extent.We use FPGA to realize the improved algorithm and compare it with the traditional algorithm.We conclude that the quality of details is greatly improved for real-time processing.