Abstract: A new method, called the strip layer method (SLM) for simulating the three-dimensional deformations of plate and strip rolling process, is presented. The rolling deformation zone is divided evenly into a number of layers along the altitudinal direction of plate or strip and every layer plate (strip) is divided into a number of streamline strip elements along metal flow traces. The streamline strip elements are mapped onto the corresponding rectangle strip elements for convenience of analysis. The longitudinal distribution model of the metal lateral displacement is constructed to be a quartic curve, its lateral distribution is expressed as a cubic spline function, and its altitudinal distribution is fitted to be a parabolic curve. From the plastic flow theory, the three-dimensional deformations and stresses of the deformation zone are formulated. Compared with the streamline strip element method (SSEM) proposed by the first author, the strip layer method considers the uneven distributions of stresses and deformations along altitudinal direction and realizes rigorous analysis. Examples of continuous rolling of hot steel strip and thick plate rolling are provided. It is shown that the method and the present model are effective. It is a new reliable method for the three-dimensional simulation of plate and strip rolling process.