The pore wettability of porous minerals plays an important role in their floatability. This paper proposed a method to reduce the pore wetting of porous active carbons using NaOL solutions with different concentrations. The in-situ pore wetting percentage of active carbon after NaOL treatments was measured by the LF-NMR and its influence on the floatability was revealed by particles-bubble attachment tests. The action mechanism of NaOL on active carbon surface was analyzed by the contact angle, zeta potential and FTIR tests. The pore wetting percentage of active carbon were gradually decreased with the increase of concentration of NaOL solutions. NaOL could interact with hydrophilic group of active carbon surfaces through electrostatic interaction, which improved its hydrophobicity and the droplet penetrating into the pores was prevented. NaOL could reduce the pore wetting of active carbon to enhance its floatability, which provides a potential guidance for improving porous mineral flotation. (C) 2020 Elsevier B.V. All rights reserved.