The invention discloses special solvent type single-ingredient polyurethane pre-coating glue for iron film coating and a preparation method thereof. The single-ingredient polyurethane pre-coating glueis prepared from polyester polyol and a curing agent. The invention also discloses a concrete preparation method. The novel special solvent type single-ingredient polyurethane pre-coating glue for the iron film coating has the advantages that the attachment force on a substrate is good; a single-ingredient bonding agent can effectively overcome the defect of long curing time of a conventional solvent type double-ingredient bonding agent; the parameters of the preparation process can be easily controlled; the environment-friendly effect is achieved in the preparation process.