Abstract:The monthly changes of contents of dissolved organic matter (DOM), as well as the spatial and temporal variations in contents and characteristics of DOM during snowmelt period, in the Xinkaihe River in Shenyang were investigated. DOM was fractionated using XAD resins into five fractions: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N) and hydrophilic fraction (HPI). The results showed that dissolved organic carbon (DOC) concentrations in river water during snowmelt period were high. HPO-N and TPI-N were the major DOM fractions, and aromatic protein- and humic acid-like fluorescent materials were the major fluorophores in DOM, during the snowmelt period. DOC, absorbance of ultraviolet light at 254nm (UV-254) and trihalomethane formation potential (THMFP) initially increased, then fluctuated, and finally decreased during snowmelt period. The changing trend of specific ultraviolet light absorbance (SUVA) and specific THMFP (STHMFP) were opposite to the above three. DOC in river water was significantly affected by the sewage discharge during snowmelt period, and DOC near the sewage outfall was higher than other areas. The indicating function of UV-254 on THMFP in receiving waters weakened as a result of the sewage discharge.