Dissolved organic matter (DOM) is a key factor that affects the environmental behavior of hydrophobic organic contaminants (HOCs). However, the relationship between the change of its DOM and the sorption capacity of HOCs during sediment ageing is unclear. The sorption and desorption of phenanthrene (Phe) on the sediments from the river and estuary flowing into sea around Bohai Bay were investigated in batch experiments in this investigation, and its change of dissolved organic carbon(DOC)content and its effects on sorption and desorption of phenanthrene during sediment ageing were also discussed. The results indicated that: ① The properties of the sediments from Jiyun river(RS)and Beitang estuary(ES)varied greatly, and the contents of TOC, TN and DOC of the sediments from RS were 13036, 1060 and 457 mg/kg, respectively, which were higher than that from ES which were 10754, 900 and 291 mg/kg, respectively. The ratio values of C and N of the sediments from RS and ES were 12.30 and 12.00, respectively, which indicated that organic matter of the two sediments, especially for RS sediment, has been highly influenced by anthropogenic sources. The ratio values of the DOC and TOC of the sediments from RS and ES were 3.50% and 2.70%, respectively.② The DOC contents of the RS(ranged from 2.4 to 347 mg/kg)and ES(ranged from 90 to 236 mg/kg)sediments trended to decrease with the ageing time prolonging. The DOC contents of the aged sediments from RS and ES decreased from 24.21% to 99.49% and from 18.71% to 69.14%, respectively. ③ The N values of Phe sorption on RS and ES samples ranged from 0.645 to 0.913 and from 0.757 to 0.872 according to the Freundlich model, respectively, which trended to decrease with the sediment ageing time increasing. The K_F values of Phe sorption on RS and ES samples ranged from 185 to 792 μg^1-n · kg^-1 · Lⁿ and 252 to 530 μg^1-n · kg^-1 · Lⁿ respectively, which trended to increase with the sediment ageing increasing. The K_F values of Phe sorption on the aged sediments from RS and ES increased from 0.50 to 3.28 and from 0.42 to1.00 times, respectively. ④ The sorption and desorption curves of Phe on RS and ES showed obvious hysteresis, and their HI decreased with the increasing of Phe concentrations in solution. Their HI values of Phe sorption on the aged RS and ES sediments increased from 1.1 to 8.3 times and from 0.7 to 10.4 times when the Phe concentrations in solution was 1 μg/L.⑤ There were significant positive correlations between the DOC contents and their N values, and the significant negative correlations were observed between the DOC contents and their K_F values. These results indicated that the change of DOC contents during sediments ageing possibly played an important role on their Phe sorption and desorption.