Accurate cross sections of neutron induced fission reactions are required in the design of advanced nuclear systems and in the development of fission theory. The time projection chamber (TPC), with its track reconstruction and particle identification capabilities, is supposed to be the best detector for high-precision fission cross section measurements. The TPC developed by the back-streaming white neutron source (Back-n) team of China Spallation Neutron Source (CSNS) was used as the fission fragment detector in the measurement. In the present work, the cross sections of the 232Th(n, f) reaction at five neutron energies in the 4.50 ~ 5.40 MeV region were measured. The fission fragments and particles could be well identified using our TPC, which leads to higher detection efficiency of the fission fragments and smaller uncertainty of the measured cross sections. Our work is the first measurement of 232Th(n, f) reaction using the TPC for the detection of fission fragments. With uncertainties smaller than 5 %, the present cross sections are consistent with the data in different evaluation libraries including JENDL-4.0, ROSFOND-2010, CENDL-3.2, ENDF/B-VIII.0 and BROND-3.1, whose uncertainties can be reduced after future improvements of the measurement.