The invention belongs to inorganic non-metallic building materials, and particularly relates to a synchronous grouting material for shield tunnels and a preparation method of the synchronous grouting material. The synchronous grouting material disclosed by the invention comprises the following components in parts by weight (kg/m<3>): 250-350 parts of a cementing material, 0-60 parts of quick lime, 0-60 parts of periclase, 0-15 parts of phosphates, 1-2.8 parts of a high-efficiency water reducing agent, 0.5-2.6 parts of polymers, 850-1100 parts of shield tailings, and 205-475 parts of water. The synchronous grouting material prepared from the shield tailings is good in early strength, micro-expanding performance, working performance and water dispersion resistance. According to the synchronous grouting material disclosed by the invention, underground tailings brought out in the process of shield construction are reasonably used, thus the impact on the environment is reduced; the synchronous grouting material is simple in ingredients, low in manufacturing cost, easy to produce, and good in workability, and can satisfy the requirements of grouting equipment.