The new waterproof material Polypropylene is used as the inner waterproof layer of the underground granary structure. The connection performance of the waterproof layer and the inner wall of the grain silo is vital to the waterproof system in underground granary structure. The technical scheme of connecting the waterproof layer with the underground grain silo wall by a new connector (threaded Polypropylene rod) is proposed. The bonding performance between threaded Polypropylene rod and concrete is investigated through experimental research and theoretical calculations, and mathematical expression of bond strength, relative slip and length of the threaded Polypropylene rod and concrete is determined. The results show that according to the experimental research and mathematical expression, it is possible to determine the bond strength, relative slip volume and limited anchor length, which provides a theoretical basis for the further design of plastic-concrete components.