A liquid-phase epitaxial lateral overgrowth (LPELO) technique combining molecular beam epitaxy (MBE) and liquid-phase epitaxy (LPE) is employed to obtain high-quality GaAs-on-Si material structure that can be used for opto-electronic applications. In this technique, first a GaAs coating layer is grown on an epitaxial Si substrate by MBE. Then, GaAs LPELO layer is grown by LPE under these conditions that the growth takes place only in the open regions formed in SiO2 film deposited on MBE-grown GaAs. It is shown that defect-free epitaxial regions can be obtained by the LPELO technique. Up to now, although some investigations on LPELO have been carried out, there has been no systematic study of the influence of underlying MBE GaAs-on-Si on the LPELO growth. In the present study, the factors that affect the ELO growth were investigated systematically. In particular,the correlation between MBE substrate and LPELO was analyzed in detail.