The invention provides a reaction bonding type node sealant and a preparation method thereof. The sealant comprises asphalt, modifiers, an emulsifier, a crosslinking agent, thickeners, a reinforcing agent and water. In the formula system, more appropriate modifiers are adopted compared with the prior art, so that a rubber asphalt mixture can achieve good emulsification effect, elasticity and strength of a sealing layer after drying are greatly improved, and the sealing effect can be good and lasting; the chemical linkage effect with concrete is formed by using the crosslinking agent, and bonding force with the concrete is improved; and a lot of thickeners are used for adjusting the stickness of the sealant system, so that the reaction bonding type node sealant can better adhere to the surface of a pentatricopeptide repeats (PPR) or polyvinyl chloride (PVC) pipe, and good sealing at positions where PPR or PVC water supply and drainage pipes are connected with base surfaces of concrete.