To establish a rolling force model with reliable prediction accuracy, a cosine velocity field was proposed according to the characteristics of metal flow in rolling process, and corresponding energy analysis was carried out based on the proposed velocity field. The proposed velocity field could strictly satisfy the volume constant condition, the boundary condition, and the geometric equation, which indicates that the velocity field can satisfy the kinematically admissible condition well. In the modeling process, the inner product and addition method of vector component was adopted to derive the internal deformation power during rolling, and the integration problem of the nonlinear specific plastic work rate of Mises criterion was solved. In addition, the mathematical expressions of friction power and shear power were derived based on the proposed velocity field. The analytical model of force-energy parameters in rolling process was obtained in terms of the variational principle of rigid-plastic material. The prediction accuracy of the rolling force model was verified by using the measured data from a domestic factory. Comparison results show that the deviations between the predicted rolling force and the measured value were within 7.55%, indicating a high accuracy. The established model was compared with the classic Sims model and Tselikov model, and a good superiority was found. In order to investigate the parameter variation during the rolling process of thick plates, the influences of reduction, shape factor, friction factor, radius-thickness ratio, and roll radius on the stress state coefficient and the position of the neutral point were analyzed.