Fe3O4/C composite materials have the advantages of both carbon-based materials and ferrosoferric oxide that more and more attention has been paid by people. Carbon-based materials have adjustable interface engineering, high specific surface area, high dielectric loss, and light weight and ferrosoferric oxide raw materials are easily obtained which have high magnetic sensitivity, easy surface functional modification and low toxicity.According to more than 200 papers published in the past 15 years, this article systematically analyzed and summarized the preparation, characterization and application of Fe3O4/C composite materials. Arc discharge method, hydrothermal method, solvothermal method, co-precipitation method and pyrolysis method were commonly used methods for preparing Fe3O4/C Ccomposite materials.Fe3O4/C composite materials could absorb heavy metal impurities in water, for example, lead, mercury, cadmium, Chromium, arsenic, etc., impurity, lead was the most common. the treatment of wastewater containing organic dyes, catalysts and activators, electrode materials and absorbing materials have been widely used.