Copolymerization of ethylene with (2‐(4‐vinylphenyl)ethene‐1,1,2‐triyl) tribenzene is conducted by using a metallocene catalyst, giving an ethylene copolymer containing tetraphenylethene unit. The result of NMR shows that the tetraphenylethene unit is distributed in isolation in the polymer chain, and the melting point of the copolymer decreases linearly with the increase of the comonomer incorporation. The copolymer can emit blue fluorescence under ultraviolet light, and the intensity increases with the increase of the comonomer incorporation. The fluorescence of flakes made of the copolymer gradually becomes weaker when the temperature is raised. When the temperature is higher than the melting point of the copolymer, the fluorescence is almost invisible.