Water reducing agent is a concrete admixture that can reduce the water consumption of mixing while maintaining the slump of concrete. Most of them are anionic surfactants. Appearance forms are water and powder. The addition of the concrete mixture has a dispersing effect on the cement particles, which can improve the workability, reduce the water consumption, and save the cement. According to the water reducing agent and water-reducing ability, it can be divided into ordinary water reducing agent, high-efficiency water reducing agent and high-performance water reducing agent. It is also divided into early strength type, standard type and retarding type. The water reducing agent has the function of dispersing cement particles to disperse the cement particles, and the flocculation structure destroys the water of the wrapped department to effectively increase the fluidity of the concrete mixture; the sliding resistance between the cement particles can be effectively reduced. Very good lubrication.