The invention discloses a high-performance concrete composite admixture and a preparation method thereof. The high-performance concrete composite admixture is prepared from the following raw materials in parts by mass: 30-60 parts of waste residues, 10-16 parts of tailings, 1-2 parts of desulfurization gypsum, 5-12 parts of powder and 1-5 parts of an activating agent. The invention also discloses the preparation method of the high-performance concrete composite admixture. The high-performance concrete composite admixture disclosed by the invention has the following beneficial effects: firstly, the raw materials of the admixture are taken from wastes to realize recycling utilization of solid wastes and solve land occupation and environmental pollution caused by stacking and burying; secondly, the admixture disclosed by the invention, by virtue of treatment and processing of the raw materials, has more excellent performance, so that the working performance and strength of each stage of concrete can be finally promoted significantly, and then the concrete becomes high-performance concrete with high durability, high applicability and high volume stability; and moreover, the admixture can greatly reduce the use level of cement and is very significant in cost reducing effect.