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Poor stability of spiro-OMeTAD hole transport materials (HTMs) with dopant is a major obstacle for the commercialization of perovskite solar cells (pero-SCs).Herein,we demonstrate a series of quinoxaline-based D-A copolymers PBQ5,PBQ6 and PBQ10 as the dopant-free polymer HTMs for high performance pero-SCs.The D-A copolymers are composed of fluorothienyl benzodithiophene (BDTT) as D-unit,difluoroquinoxaline (DFQ) with different side chains as A-unit,and thiophene as π-bridge,where the side chains on the DFQ unit are bi-alkyl for PBQ5,bi-alkyl-fluorothienyl for PBQ6,and alkoxyl for PBQ10.All the three copolymers are adopted as the dopant-free HTM in the pero-SCs.The planar n-i-p structured pero-SCs based on(FAPbI3)0.98(MAPbBr3)0.02 with PBQ6 HTM demonstrated the high power conversion efficiency (PCE) of 22.6％ with Voc of 1.13 V and FF of 80.8％,which is benefitted from the suitable energy level and high hole mobility of PBQ6.The PCE of 22.6％ is the highest efficiency reported in the n-i-p structured pero-SCs based on dopant-free D-A copolymer HTM.In addition,the pero-SCs show significantly enhanced ambient,thermal and light-soaking stability compared with the devices with traditional spiro-OMeTAD HTM.