The invention discloses a gold/carbon compound microsphere and a preparation method thereof. The preparation method comprises the following steps: firstly, stirring a glucose solution under a shielding condition; adding a prepared chloroauric acid solution and then slowly adding a defined amount of trioctylamine; putting the mixed solution into an ultrasonic cleaner for ultrasonically scattering, thereby preparing a milk white micro-emulsion; heating the emulsion through hydrothermal reaction; naturally cooling till room temperature; centrifugally separating the reaction liquid; repeatedly cleaning precipitate alternately with water and absolute ethyl alcohol and drying under vacuum; lastly, and annealing the product under Ar protection, thereby acquiring the gold/carbon compound microsphere. The method provided by the invention is simple in operation; the agglomeration problem of nanometer gold particles is solved; the utilization efficiency is increased; the gold/carbon compound microsphere prepared according to the method is uniform in size distribution; the nanometer gold particles are embedded in a carbon shell; the carbon shell thickness and the size of the nanometer gold particles loaded on the carbon shell both are in nano-scale; the dispersity is excellent; the high performance of nanometer gold is fully utilized.