The invention belongs to the technical field of lithium-ion battery materials, and discloses a graphene-based FeS2 nano-material and a preparation and an application thereof. The preparation method comprises the following steps: ultrasonically dispersing graphene oxide into water to obtain a graphene oxide suspension liquid, adding a reducing agent for ultrasonic treatment and then obtaining a graphene suspension liquid; adding Na2S and S to water, heating, stirring and dissolving the Na2S and the S evenly to obtain an Na2S2 solution; dissolving FeSO4 into water and mixing the solution with the graphene suspension liquid; and adding the Na2S2 solution, heating the Na2S2 solution to 100 DEG C, carrying out reflux reaction in an inert gas atmosphere for 0.5-3 hours, and centrifugally separating, drying and grinding a reaction product to obtain the graphene-based FeS2 nano-material. The obtained material can be applied to a negative electrode of the lithium-ion battery, and is relatively high in specific capacity and relatively good in performance under a high-rate condition.