The invention discloses a method of embedding nuclei inside hyriopsis schlegeli for breeding oversized round-shaped pearls. Nucleus inserting is used once or twice. The method is characterized in that the nucleus inserting method includes the following steps: after a pearl breeding oyster opens and is added with a plug, and dirt inside the oyster is cleared away, using a wound needle to wound the position of half of the axe foot width and 40%-45% (counting from the back end, and the same below) of the axe foot length of the pearl breeding oyster to obliquely downwards pass a visceral mass towards a front end to wound horizontally, and then pulling out the needle in the position of 55%-65% of the visceral mass, and implanting a bead nucleus and cell bodies in the position of a wound, wherein the position of the implanted bead nucleus includes that a central point is in the position of 60%-75 % of the length of the visceral mass, the edge of the upper end of the bead nucleus adjoins the connecting position of an axe foot and the visceral mass, a nucleus sending needle is pulled out, the position of the wound is smoothed, and the plug is pulled out after inflammation is diminished in the wounds; after being operated, hanging and breeding the pearl breeding oyster in a repairing pool, after the wound heals, hanging and breeding the pearl breeding oyster in a breeding pool. Due to the facts that space in the visceral mass and the visceral mass positions of the oyster is large, an oversized pearl can be borne inside the oyster and cannot be squeezed. Therefore, oversized top-grade high-quality pearl products can be bred.