The roll-platen forming process is a novel process aimed at producing elongated components to net shape or near net shape. Systematic research has been conducted: (1) to establish the general mass flow mode under various process parameters by physical modelling; (2) to further investigate the effect of speed ratio and aspect ratio on curvature of hot steel roll-platen formed components by finite element simulation. This paper presents the results of FE investigation of the effect of aspect ratio on curvature including the characteristics of progressive deformation, the development and distribution of generalised plastic strain, and the deformed workpiece shape. These simulated curvature results agree closely with those of physical modelling experiments. Some special boundary techniques developed for this FE modelling will also be briefly mentioned in this paper.