The invention discloses a neutral descaling agent and a preparation method of the neutral descaling agent. The neutral descaling agent comprises a supramolecular descaling agent monomer solution, a surfactant and a pH adjuster. A supramolecular descaling agent monomer is prepared by adopting the special raw material proportioning ratio, is safe and long-acting and does not chemically react with scale and metal; through dispersion and molecular assembly, stripping and scale decomposition are achieved, and finally stable adhesion to the metal surface can be achieved; and oil scale, dirt, crystalscale, rust scale and the like which are difficult to clean by conventional chemical cleaning can be removed, a compact protective film is formed, long-term stable operation of an oil well can be maintained, subsequent scale formation can be prevented, and long-acting descaling and scale inhibition can be achieved.