The invention relates to a method for synthesis of a lithium iron silicate/graphene composite positive electrode material, and belongs to the technical field of lithium ion battery. The method comprises the steps: pickling rice husks, washing, filtering and drying to obtain rice husks having alkali metal oxide impurities removed; under an aerobic condition, carrying out low-temperature oxidation of the rice husks having the alkali metal oxide impurities removed to obtain carbon-containing rice husk ash; adding a lithium source into the carbon-containing rice husk ash, and mixing evenly to obtaining a mixture; carrying out annealing activation of the mixture at the temperature of 600-900 DEG C for 1-12 h, and thus obtaining a Li2SiO3/graphene composite material; adding an iron source into the Li2SiO3/graphene composite material, and then carrying out wet grinding of the material; and under an inert atmosphere, baking the wet-ground material at the temperature of 500-800 DEG C for 1-20 h, then cooling to the room temperature, washing with deionized water, and drying to obtain the lithium iron silicate/graphene composite positive electrode material. The method realizes the high additional value application of agricultural waste.