Abstract: In delivery of the cleaned low-rank weakly-caking coal product, the freight tonnage is liable to be reduced due to reduction of surface moisture of coal. To tackle this problem, work is made on enhancement of the hydrophilicity of the coal surface through surface modification with wetting agent, so as to enable the coal to retain its surface moisture during transportation. Exploration of the mechanism of the wetting agent is made by means of IR, Raman and XPS analysis. It is found after surface modification the coal surface is attached with hydroxyl and carboxyl groups which help enhance the hydrophilicity of coal surface because of increase of ratio of O/C contents and sharp decrease of contact angle.