The influence of surface structure on epitaxial growth, which has not been considered before in the crystal growth theory, is shown for the case of epitaxial growth of Si on Si(111)-7×7 substrate. In the lateral growth of islands on the 7×7 structure, the island size shows a discontinuous distribution according to the size of the unit cell of the surface structure, because the rate determinant process is the rearrangement of the surface lattice. This size distribution is understood by considering the activation energy of the rearrangement into the free energy change in the nucleation process. The surface structure also influences on the growth mode. In the initial growth stage, multilayer islands are formed because the lateral growth of the first layer is prevented by the stable 7×7 structure and some migrating atoms climb up the first layer and nucleate on it. However, the lateral growth of the second layer on the first one is not prevented and the layer-by-layer growth starts, because the structure of the first layer is composed of small domains with some metastable surface structures which is rather easier to rearrange than the 7×7 structure.