The invention provides a composite concrete crack-resisting agent, and belongs to the technical field of building materials, the crack-resisting agent is prepared from the following components in percentage by mass: 3-7% of polypropylene glycol, 7-10% of polyvinyl alcohol, 1-3% of VAE emulsions, 0.01% of defoaming agent, 10-15% of nan-zinc oxide, 3-5% of methyl sodium silicate and the balance of water, the preparation method includes the steps of 1) adding polyvinyl alcohol into cold water to overflow to-be-volatilized substances, increasing the temperature through water-bath heating to accelerate dissolution, insulating heat until the solution does not contain microparticles, filtering the solution, and lowering the temperature to room temperature for standby use; 2) evenly stirring polypropylene glycol, the VAE emulsions and the water to obtain mixed liquid A; 3) putting polyvinyl alcohol solution and the mixed liquid A in a stirrer, adding nano-zinc oxide, methyl sodium silicate andthe defoaming agent, and performing uniform stirring to obtain the concrete crack-resisting agent, the composite concrete crack-resisting agent has the advantages that surface moisture evaporation ofconcrete can be inhibited obviously, plastic shrinkage of the concrete can be reduced, surface cracking of the concrete can be resisted, and durability of the concrete can be improved.