The invention relates to a preparation method and application of a bimetallic oxide / carbon composite material, belonging to the technical fields of composite material preparation and water treatment. The preparation method comprises the following steps: dropwise adding mixed salt solution of magnesium nitrate or zinc nitrate and aluminum nitrate and mixed alkaline solution of sodium hydroxide and sodium carbonate into a breaker which is heated at the temperature of 60 DEG C and filled with distilled water, controlling pH value to be about 10, continuously stirring for 6-12 hours, and standing for 3-6 hours, thus obtaining turbid liquid of hydrotalcite; adding congo red wastewater into the turbid liquid of hydrotalcite, and oscillating for 3 hours; then drying, smashing, putting into a high-temperature tube furnace, and heating for 2-4 hours at the temperature of 500-800 DEG C under the action of nitrogen, thus obtaining the bimetallic oxide / carbon composite material; and when the bimetallic oxide / carbon composite material is applied to removal of lead, cadmium and copper ions in water, the good effect is realized. The prepared bimetallic oxide / carbon composite material has the advantages that a preparation technology is simple, conditions are easy to control, the adsorption capacity is high, heavy metal ions in water can be effectively removed, and composite material preparation and adsorption process is environmentally friendly.