The invention discloses a preparation method of small mantle pieces. The method comprises the following steps that mantle taken from the shell of pearl oyster is placed on a glass plate and repeatedly scratched in one direction through a sheet with smooth edges to enable the mantle to be unfolded and straightened; mucus on the surface of the mantle is removed with a bentonite sea water suspension, and the small mantle pieces are cut and prepared on a wood plate by taking a stainless steel sliver as a template. According to the preparation method of the small mantle pieces, operation of all the steps is easy, the difficulty of preparing the small mantle pieces is greatly reduced, preparation can be mastered through simple guidance, and the preparation method not only can be used for culture and production of pearls, but also can be used for pearl culture experience tourism to enable tourists to experience the preparation process of the small mantle pieces.