The present invention discloses an efficient shrinkage-reducing anti-cracking agent and a preparation method thereof, the efficient shrinkage-reducing anti-cracking agent comprises a shrinkage-reducing component and an expansion component, the shrinkage-reducing component is a shrinkage-reducing agent is a comb-shaped copolymer shrinkage-reducing agent, the expansion component is a calcium oxide type expander, and the mass ratio of the shrinkage-reducing component to the expansion component is 35: 65-45: 55. The shrinkage-reducing component is absorbed on the surface of the expansion component by spray drying, the expansion component is used as an anti-blocking insulating material to achieve fine powder production of the liquid shrinkage-reducing component, the shrinkage-reducing component is used as a waterproof insulation material to delay early hydration of the expansion component, and ultimately coordination and integration of expansion and shrinkage educing is achieved; by powder production and application, injuries of volatile organic solvents on workers during single use of the shrinkage-reducing agent can be avoided, the effective content of the product can be increased, the efficient shrinkage-reducing anti-cracking agent has a significant anti-cracking effect under conditions of low dosage, and helps are provided for expansion of the use range of anti-cracking materials.