The invention discloses a preparation method of photocured rare earth europium modified abietic acid composite polymer. The photocured rare earth europium modified abietic acid composite polymer is specifically a composite polymer prepared from a rare earth abietic acid complex, a trifunctional aliphatic urethane acrylate, a difunctional aliphatic urethane acrylate, an alkyl methacrylate ester reactive diluent, photoinitiator, a flatting agent and a stabilizer component by mixing, film formation, ultraviolet curing and other treatment methods. The composite polymer has the advantages of simplepreparation method and environmental friendliness, and is suitable for industrial production; the rare earth abietic acid complex contains a hydrogenated phenanthrene ring structure, which imparts excellent thermal stability to the composite polymer hereof, and also improves gloss, flexibility, hardness, etc. The composite polymer has good fluorescence performance, can emit special red fluorescence of europium ions, and has a wider excitation peak wavelength range in a near-ultraviolet region of 300-400 nm; the coating curing time of the composite polymer hereof is short, the speed is high, and the coating has good overall performance.