It consists of water-based epoxy resin, water-based epoxy curing agent, and auxiliary agent. It is divided into two components, A and B, and water is used as a thinning agent. Water-based primer has a low viscosity and can penetrate into the pores of the cement base. The polymer formed after curing has a three-dimensional network cross-linked structure. This structure is tough and strong, insoluble and infusible, and firmly bonded to the cement base. It prevents the groundwater vapor from penetrating upwards, and has the functions of resistance to water, acid, alkali, salt, and chemical solvents. It can consolidate the powdery loose substance on the surface of cement, which is conducive to improving the bonding strength between the floor coating and the cement interface. The change in the appearance of the coating can also determine whether the humidity of the cement floor is suitable for construction. Transparent primer is suitable for new cement floor.