Abstract: The standard FCM algorithm is noise sensitive because of not taking spatial information into account, and it considers that each feature datum has the same contribution to classifying results. To overcome the above problems, this paper presented a modified FCM algorithm accounting for pixel spatial information based on gray histogram weight. The proposed algorithm was realized via introducing a gray histogram weight in the objective function given in Szilagyi's algorithm. Experimental results on both artificial synthesized images and realistic images demostrated the sound performances of the proposed algorithm.