The invention discloses a concrete synergist. The concrete synergist is prepared from the following raw materials in percentage by mass: 7%-12% of acrylic emulsion, 2%-3% of sodium dodecyl sulfate, 5%-7% of polyalcohol, 5%-10% of triisopropanolamine, 10%-15% of nano calcium carbonate, 3%-5% of diethylenetriamine-5-tetraoxaoctadecanoicacid, 2%-4% of sodium lignosulfonate, 1%-3% of nanometer silicongranules, 10%-15% of octyl phenolic tackifying resins and the balance of water. According to the concrete synergist disclosed by the invention, gaps in concrete can be stuffed, the bending tensile strength and the permeability resistance of the concrete are improved, the concrete is endowed with high mechanical force resistant performance, the problem of large time loss in collapsed slump of theconcrete is solved, the frost melting resistant capacity and the durability of the concrete can be improved at the same time, and the service life of the concrete can be prolonged.