Grinding is widely used in ore size reduction. In this investigation, grinding is proved to be advantageous in improving the floatability of anthracite coal of mild oxidation. FTIR was used to explain changes in the main functional chemical groups of anthracite coal of mild oxidation upon grinding. Improvements of the floatability of four size fractions, namely, +0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm and -0.074 mm, were discussed respectively. The results show that the floatability of anthracite coal of mild oxidation can be improved by 30 minutes grinding. The anthracite coal of mild oxidation can obtain many fresh hydrophobic surfaces by scuffing. Besides, the anthracite coal of mild oxidation can be crushed and/or ground to form fines which also contain many fresh hydrophobic surfaces. Combustible matter recovery of anthracite coal of mild oxidation, ground by 30 minutes, can reach 72.14% with ash content of 8.63%, while combustible matter recovery of original coal is 56.65% with ash content of 9.90%.