Abstract: The median filtering algorithm can improve the influence of the noise to a large extent,but make the picture edge misty. Aiming at this problem a new salt and pepper noise detection algorithm is proposed in this paper. The salt and pepper noise of image can be detected by applying this algorithm,and then filtered by median filtering algorithm. The experiments proved this algorithm being able to remove salt and pepper noise effectively. So,the better result can be obtained in the case of serious noise.