The invention belongs to the technical field of nanometer materials, and particularly relates to a morphology-controlled carbon quantum dot / nickel cobaltate composite electrode material and a preparation method. The preparation method specifically comprises the following steps of (1) dissolving carbon quantum dot powder, nickel nitrate hexahydrate, cobalt nitrate hexahydrate and urea into a mixed solvent of water and ethanol, mixing, putting into a polytetrafluoroethylene-lined reaction kettle, adding foam nickel, sealing, heating to react, cooling, taking out foam nickel, flushing and drying; (2) performing heat treatment on the dried foam nickel, so as to obtain the carbon quantum dot / nickel cobaltate composite electrode material using the foam nickel as a substrate. The preparation method has the advantages that by adjusting the feeding amount of carbon quantum dots, different morphologies of the composite material, such as urchin shape, corolla shape and waxberry shape are formed on the micro structure; the preparation method is simple, the implementing is easy, and the cost is low; the chemical and physical property of obtained material is stable, and the application prospect is good in the fields of electrochemical energy storage and catalyzing.