The invention discloses a preparation method for a flocculus-shaped SnS<2> negative electrode material of a lithium ion battery. The preparation method comprises the steps of 1) dissolving sodium thiosulfate into deionized water to prepare a solution A, and dissolving stannic chloride pentahydrate into deionized water to prepare a solution B; 2) adding the solution B into the solution A dropwise, continuously stirring to obtain a uniform mixed solution C, and gradually adding ethylene glycol into the mixed solution C to form a uniformly-mixed solution D; 3) adjusting the pH of the mixed solution D to be 2-9 to form a solution E; 4) putting the solution E into a homogeneous hydrothermal reaction kettle to be sealed, and then putting into a homogeneous hydrothermal reactor to be reacted; and 5) after the reaction is completed, taking out a precursor, and performing centrifuging and washing by deionized water and absolute ethyl alcohol separately, and then performing freezing and drying to obtain the flocculus-shaped SnS<2> negative electrode material of the lithium ion battery. The preparation method is low in cost, simple in operation and short in preparation period; and the prepared flocculus-shaped SnS<2> negative electrode material of the lithium ion battery has relatively high cycling stability at high-current density.