The invention provides a self-repairing cement-based composite material. The composite material is characterized in that the composite material is prepared from the following materials by mass percent: 35 to 75 percent of cement, 5 to 35 percent of slag powder, 20 to 55 percent of active substance and 3 to 7 percent of water repellent. The preparation method of the active substance comprises the following steps: taking the following materials by mass percent: 1 percent of stearic acid, 59 percent of cement, 18 percent of anhydrite and 22 percent of calcium hydroxide, grinding the four materials into a mixture A with 4000 to 6000 meshes by a flour mill, completely bonding the stearic acid to the cement, the anhydrite and the calcium hydroxide, then adding the mixture A into a large cyclodextrin (LR-CD) saturated solution to fully stir, performing clathration on the cement, the anhydrite and the calcium hydroxide to dry by utilizing the hydrophobicity of the stearic acid and the lipophilic and hydrophobic properties of the inner cavity of the LR-CD. The self-repairing cement-based composite material provided by the invention has the advantages that the composite material has a self-repairing function on the crack on the concrete and reduces the occurrence rate of engineering accident.