The invention discloses an additive for a warm-mixed regenerative asphalt mixture. The additive is prepared from the following raw materials in parts by weight: 7-9 parts of a warm mixing agent, and 2-4 parts of a regenerant; the warm mixing agent is prepared from the following raw materials in parts by weight: 100 parts of resin, 5-10 parts of a surfactant, and 30-50 parts of a turpentine emulsion; the surfactant is prepared from the raw materials of tall oil and concentrated sulfuric acid with the molar ratio being 10:(4 to 6); the turpentine emulsion is prepared from the raw materials in parts by weight: 10 parts of turpentine, and 1-2 parts of acetic acid; and the regenerant is prepared from the following raw materials in parts by weight: 1-3 parts of sorbitol, 4-6 parts of aluminum stearate, and 7-9 parts of furfural extract oil. The invention further provides a preparation method of the additive for the warm-mixed regenerative asphalt mixture, and a warm-mixed regenerative asphalt pavement mixture. The additive for the warm-mixed regenerative asphalt mixture simultaneously has the functions of warm mixing and modified regeneration, cold adding of RAP is achieved, and performance of aged asphalt is recovered.