A metal-matrix dispersion fuel plate is considered. Taking account of the actual geometry, a special three-dimensional representative volume element is developed according to the particle distributions, which might characterize not only the macro deformation along the thickness but also the micro stress-strain fields. An elastoplastic analysis using the finite element method is carried out for the thermal-mechanical behaviors induced only by the thermal effects. The distributions of the thermal stresses at the fuel particles and the matrix are given, and the effects of the surface heat transfer coefficients, the heat generation rates of the fuel particles, and the degraded conductivities of the fuel particles along with the burnup on the stresses and the size variations of the plate thickness are investigated. The research results indicate that the internal stress distributions are not spherically symmetrical. With increasing surface heat transfer coefficients, the first principal stresses at the particles and the matrix both fall, and the thickness increments decrease. The first principal stresses at the fuel particles and the matrix both grow with increasing heat generation rates, and the thickness variations linearly increase. With decrease of the thermal conductivities of the fuel particles, the first principal stresses at the matrix increase, and the relative stresses at the particles decrease.