The invention relates to a seed crystal laying method which comprises the following steps: A, manufacturing monocrystalline silicon columnar seed crystals with orthohexagonal sections, wherein the section normal direction of the monocrystalline silicon columnar seed crystals is <100> crystal orientation and the crystal orientation of the side surface normal direction is not required specifically; B, laying the side surfaces of the seed crystals on the bottom surface of a crucible fully in a close fit manner, wherein that the side surfaces of the seed crystals are in close fit is taken as a standard. According to the invention, the vertex angle seam of each monocrystalline silicon columnar seed crystal with the orthohexagonal section is reduced to three from four in comparison with that of the traditional quadrilateral seed crystal and is reduced by 25%, so that the probability of defects at the vertex angle is reduced greatly. In addition, the orthohexagonal seed crystals can splice into regular triple-junction crystal boundaries (the inclined angles are 120 degrees), so that greater heat stress can be borne, defect formation and increase caused by heat stress in a growth process can be restrained, the minor carrier lifetime of silicon wafer bodies is prolonged and the conversion efficiency of preparing the silicon wafers into battery pieces is improved. On the other hand, the invention provides a single crystal growth method through ingotting.