With a view of simulating the dimensional changes during sintering of rectangle green bodies, the thermo-mechanical behavior of zirconium powder compacts at high temperature is investigated. In order to better describe the behavior of anisotropic shrinkage, the revised Master Sintering Curve is modified. Finite element calculations are then carried out on the green body according to the modified equation with the different shrinkages coefficients at the different stages of sintering. The possible causes of the anisotropic shrinkage are explained by macro-surface energy model. Numerical shape predictions have been compared with experimental data, which are considered to be in good agreement.