Cone spinning is an advanced but complex metal forming process under coupled effects of multi-factors. Understanding the deformation mechanism, i.e., the stresses, strains, and metal flow in the deformation zone during the process is of great significance for optimizing the spinning process and controlling the product quality. In this paper, based on ABAQUS/Explicit, a reasonable FEM model for cone spinning with a single roller has been established, and the features of stress, strain and wall thickness during the process have been obtained. The results show the following: (1) In the beginning, large stress, large strain and the acute thinning of wall thickness localize at the small region below the roller, then the region extends into a small ring, further it becomes a large ring, and finally the ring will become uneven if the wrinkling occurs in the flange. (2) After spinning, the acute thinning region locates at the midst of the wall near the bottom of the workpiece. (3) At earlier stage of cone spinning, as a result of the acute thinning of wall thickness in the wall zone, the unevenness of wall thickness increases sharply to a value, then it almost keeps the value at the stable stage, and finally it will slowly increase again if the wrinkling appears in the flange. The results are helpful for determination and optimization of process parameters of cone spinning.