Segmentation of infrared (IR) ship images is always a challenging task, because of the intensity inhomogeneity and noise. The Fuzzy C-Means (FCM) clustering is a classical method widely used in IR ship image segmentation. However, it has some shortcomings, like not considering the spatial information or being sensitive to noise. In this paper, an improved FCM algorithm based on the spatial information is proposed. The improvements include two parts: (1) adding the non-local spatial information based on the ship target; (2) using the spatial shape information of the contour of the ship target to refine the local spatial constraint by Markov Random Field (MRF). A preprocessing procedure and a target selection method are also used to further improve the performance of the segmentation result. Experimental results show that our method is very effective and performs better than the conventional FCM methods in segmentation of the infrared ship images.