XPS, SEM and contact angle measurements were used to indicate the changes in surface properties ofanthracite coal before and after inside/outside weathering processes. Weathering processes of anthracitecoal were conducted on the roof and in the room respectively. XPS results showed that the contentof C C and C H groups on the surface of anthracite coal was decreased after weathering processeswhile the content of C O, C O and O C O groups was increased. SEM results showed that the surfaceroughness of anthracite coal was increased after the weathering processes. Contact angle measurementsshowed that the contact angle of weathered coal was lower than that of fresh coal. Throughout this paper,it was found that inside weathering processes were less intense than outside weathering processes.The hydrophobicity of anthracite coal was less changed by inside weathering processes than outsideweathering processes. Hydrophobic coal surface should be more useful for the flotation processes of finecoals than hydrophilic coal surface. It was recommended that storing coal inside, such as in the room orin the raw coal barns could avoid the heavy weathering processes.