A novel monomer containing tetraphenylethylene-(2,6-difluorophenyl)(4-(3-(4-1,2,2-triphenyl vinyl)phenoxy)propyl)phenyl)methanone (2F-TPE) was designed and synthesized by reaction of (4-(3-bromopropyl)phenyl)(2,6-difluorophenyl)methanone and 1-(4-hydroxyphenyl)-1,2,2-triphenylethene. A series of high fluorescence intensity poly(aryl ether ketone) copolymers containing tetraphenylethylene (TPE–PAEK) were prepared, which is the first report of preparing PAEK featuring tetraphenylethylene groups by polycondensation. The fluorescence and thermal properties of TPE–PAEK were characterized using fluorescence spectrophotometer, differential scanning calorimetry and thermogravimetric analysis respectively. The results indicated that tetraphenylethylene-based copolymers possessed high fluorescence intensity at a low concentration both in solids and in water/THF mixtures. TPE–PAEK still presented strong fluorescence intensity at elevated temperature up to 90 °C. In addition, TPE–PAEK possess excellent thermal stability.