A simple 1-D numerical model to predict the effect of mold-vibration on the solidification of metals is presented. Mold-vibration during solidification is known to have profound effect on the microstructure and mechanical properties of castings. However, its working mechanism is not well understood yet. Inverse heat conduction method is used to estimate mold/casting heat transfer coefficient, and phase-change during the solidification of Al-12.6%Si. The results for different conditions of vibration are compared. Numerical simulation results show that mold-vibration has changed the heat transfer coefficient in a way dependant on the frequency and amplitude used. Mold-vibration also assisted the phase-change process, by reducing nucleation time and in some cases reducing the solid growth time.