The mole fraction distributions of CaO and SiO2 under a temperature gradient in a CaSiO3 melt were calculated by molecular dynamics. The temperatures at the cold and hot ends of the gradient were 1800 and 2200K, respectively, in the simulation. We used two sets of potential parameters proposed by Matsui et al. and Seo et al. The simulation results obtained with the two potentials indicate that the mole fraction of CaO in the cold region was higher than that in the hot region, and the mole fraction of SiO2 in the hot region was higher than that in the cold region. This is qualitatively consistent with previous experimental results obtained by laser local heating inside a CaSiO3 glass.