The invention discloses an additive for an electrolytic copper foil, an electrolytic copper foil manufacturing process and the electrolytic copper foil. The additive consists of a copper brightener, gelatin, carboxyl cellulose, a leveling agent, a wetting agent and water, wherein the weight ratio of the copper brightener to the gelatin to the carboxyl cellulose to the leveling agent to the wetting agent to the water is 0.1: 5: 1: 0.2: 0.4: 50. The additive for the electrolytic copper foil controls the brightness of the copper foil in such a manner that the carboxyl cellulose is used for assisting in the copper brightener, so that the copper coil not only has moderate brightness, but is also free from rough surface. The electrolytic copper foil manufacturing process has the advantages of being simple in operation and low in cost, and the prepared electrolytic copper foil has the advantages of quite high thickness, low profile, large area, no porosity, good thickness uniformity, high purity, excellent electric conductivity and the like, is capable of meeting the demands of medical apparatuses and military industry, and can be widely applied to information shielding safety products, military products or medical apparatus products.