Shenfu subbituminous coal (SFSBC) and pretreated SFSBC with H2O2 were subjected to oxidation with NaOCl at 30 degrees C for 5 h. The results show that the pretreatment with H2O2 significantly increased the yields of water-soluble species (WSS), especially benzene carboxylic acids (BCA) and long-chain alkanedioic acids (LCADA), but substantially inhibited the formation of chloro-substituted alkanoic acids. The introduction of oxygen functional groups to SFSBC by the pretreatment (LCADA) could be responsible for the increase in the yields of WSS, especially BCA and LCADA.