X-ray photoelectron spectroscopy (XPS) was used to indicate the chemical properties of Taixi oxidized coal. The results of XPS analysis showed that Taixi oxidized coal contained many oxygen functional groups. The results of our previous studies (conventional flotation tests using diesel as collector) indicated that Taixi oxidized coal was difficult to float. A concentrate yield of 24.89% could be only obtained even at a very large diesel dosage (25 kg/t coal). Therefore, reverse flotation was introduced to upgrade Taixi oxidized coal in this investigation. Dextrin and hexadecyl trimethyl ammonium bromide (HTAB) were used as depressant and collector, respectively. The effects of dextrin and HTAB dosages on reverse flotation behavior of different size fractions (−0.5 + 0.25 mm, −0.25 + 0.125 mm, −0.125 + 0.074 mm and −0.074 mm) were also discussed. Both dextrin and HTAB dosages had a significant effect on reverse flotation behavior of coarse coals (−0.5 + 0.25 mm and −0.25 + 0.125 mm) but had a little effect on reverse flotation behavior of fine coals (−0.125 + 0.074 mm and −0.074 mm). Throughout this study, reverse flotation was found to be especially suitable for the upgrading of Taixi oxidized coal.