Polycrystalline silicon wafers for high efficiency solar cells were produced using the casting method. Mathematical modeling and numerical computations were made to investigate the effects of geometric parameters and termal parameters of the casting equipment, that is, the wall thickness of the crucible, the cooler diameter, the cool-ing rate, and wall temperatures of the crucible on the crystalline structure and size of the silicon ingot. The growth of polycrystalline with the columnar structure and large grain size was predicted to be favored by the following conditions of parameters; i)making the side wall of crucible as thick as possible and the bottom as thin as possible, ii)keeping the higher temperature profile in the top compared to the side wall of the crucible and lowering the cooling rate as the soli-dification proceeds.