Abstract: Previous researches on the optoelectronic properties of polybenzoxazole (PBO) and triphenylamine derivatives inspirited the idea of introducing triphenylamine with excellent hole transport properties into PBO backbone. Three precursors (MeTPA-PrePBO) with super solubility were synthesized via condensation-copolymerization, using 4, 4'-dicarbonyl chloride-4"-methyltriphenylamine (MeTPADC), terephthalyl chloride (TPC) and 4, 6-di(tert-butyldimethylsilylamino)-1, 3-di(tertbutyldimethylsiloxy)benzene (TBS-DAR) as materials. And then a cyclodehydration process was carried out, forming a rigid structure to produce final copolymers MeTPA-PBO. The electron transport property of oxazole ring and hole transport property of triphenylamine were combined to form an unprecedented novel photophysical material. Methyl-triphenylamine groups and oxazole rings were arranged alternately in polymer backbone, forming new highest occupied molecular orbital (HOMO) energy and lowest unoccupied molecular orbital (LUMO) energy, which made copolymers contain methyl-triphenylamine moieties possess narrower band gap to give better performance. Meanwhile, the introduction of large methyl-triphenylamine group reduced the rigidity of the compolymers so that the chains of copolymers tended to show better solubility. The structure, solubility, thermal stabilities and photophysical properties were characterized by Nuclear Magnetic Resonance spectroscopy (¹H-NMR), Fourier Transform Infrared spectroscopy (FT-IR), Thermogravimetry (TG), UV-Vis spectrophotometer (UV-Vis) and fluorescence spectra. Results showed that three precursors had excellent solubility in organic solvents, and the copolymers also had certain solubility in some high boiling solvents, such as dimethyl sulfoxide (DMSO). MeTPA-PBO showed excellent thermal stability at high temperature environment even at more than 500℃ in both nitrogen and air atmosphere. Copolymers possessed a narrow band gap(about 2.0 eV)and demonstrated strong and stable fluorescence intensity.