Abstract: The shrinkage reducing agent of poly-acrylate is mainly composed of crylic acid、cinnamene、poly－glycol、solicitating agent、chain transferring agent and activator, and passed through the processes of polymerization、esterifing and neutralization to form a pectinate polymer, that has a high molecular weight and many poly-oxidative alkenes. The dosage of this agent is in 0.3%～2.0% of mass of the cement in concrete. The shrinkage reducing rate can reach to 50%～70% at the 7th day, and 40%～50% at the 28th day. It doesn′t reduce the compressive strength of the concrete, and has an ability of 10%～18% of water reducing rate. It can retard the setting time of the concrete. It also can be sprayed on the surface of concrete members as a curring agent, and have a good shrinkage reducing effect.