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This invention discloses a method for preparing gold-coated silica nanoparticles with an egg yolk shell structure. The method involves adding trisodium citrate solution, tannic acid solution, and sodium carbonate solution to a flask and stirring. After heating, chloroauric acid solution is added, and stirring continues while maintaining a certain temperature to obtain a gold nanoparticle solution. The gold nanoparticle solution, anhydrous ethanol, ammonia, and hexadecyltrimethylammonium bromide are then added to the flask, stirred, and resorcinol is added, with continued stirring. After the reaction, formaldehyde is added dropwise, followed by tetraethyl orthosilicate. The reaction product is washed multiple times with deionized water by centrifugation, dried overnight in an oven, calcined, and then washed multiple times with deionized water by centrifugation and dried in an oven to obtain gold-coated silica nanoparticles with an egg yolk shell structure. This one-pot sol-gel method is low-cost, simple, and rapid, producing gold particles with uniform morphology, a uniform silica shell thickness, and a large internal space within the egg yolk shell.