A series of conjugated copolymers(PT-TFQ, PTT-TFQ and PTTT-TFQ) based on fluorinated thiophenequinoxaline(TFQ) were designed and synthesized by Stille reaction using thiophene, 2,2′-bithiophene or 2,2′∶5′,2″-terthiophene as the donor, and the fluorinated quinoxaline thiophene as the receptor, respectively. The structures were characterized by ¹H NMR. The effects of different number of thiophene rings on UV-Vis absorption spectra, energy levels, electrochemical behavior and photovoltaic performance were systematically investigated. The results showed that λ_max of PT-TFQ, PTT-TFQ and PTTT-TFQ in CHCl₃ solution were 545 nm, 578 nm and 649 nm, and exhibited a red shift of 81 nm, 97 nm and 44 nm in film, respectively. The open circuit voltage of PTTFQ, PTTTFQ and PTTTTFQ were 0.86 V, 0.60 V and 0.50 V, and the polymer solar cells based on them exhibited power conversion efficiencies of 3.19%, 3.10% and 2.63%, respectively.