The invention discloses a method for preparing a granular assembly spherical SnS<2> sodium ion battery anode material. The method is characterized by comprising the following steps of: (1), dissolving SnCl<4>5H<2>O in deionized water to prepare solution A, and dissolving thioacetamide in the same amount of deionized water to prepare solution B; (2), dropwise adding the solution B into the solution A under the magnetic stirring action, continuously stirring to obtain uniformly mixed solution C, and continuously stirring after dropwise adding NaOH solution to form solution D; (3), putting the solution D in a microwave hydrothermal reaction instrument, and reacting in a homogeneous-phase hydrothermal reactor; and (4), after reaction is ended, taking out a precursor, respectively performing centrifugal washing through deionized water and absolute ethyl alcohol, and freezing and drying so as to obtain the granular assembly spherical SnS<2> sodium ion battery anode material. The method disclosed by the invention is low in preparation cost and short in preparation period; furthermore, the prepared granular assembly spherical SnS<2> sodium ion battery anode material has excellent electrochemical performance.