Water-soluble pitch containing more than 70% of hydrophilic groups were prepared from the oxidation of coal tar pitch in the presence of acid, the product can be applied in the preparation of composite carbon materials in aqueous medium owing to a variety of introduced polarity groups and normal condensed rings. Moreover, the molecular structure was analyzed using Fluorescence, IR, UV, NMR and Yen-Mullins model. The results indicated that the fraction of N, O, S were increased by 1.06%, 11.64%, 0.79% to 6.78%, 29.59% and 2.41% respectively. In addition, the hydrophilicity of the desired pitch enhanced that was attributed to the O percent increased. Hetero-atoms (N, O, S) exist in the form of Ar—NO2, Ar—OH, Ar—SO3H and CO were characterized by infrared spectroscopy. Three fused aromatic rings called “Island structure” were identified by fluorescence and Yen-Mullins model, substitutions on aromatic rings were oxidized to a single C-atom group as shown by 1H-NMR and 13C-NMR spectra, this group and “Island structure” can be seen as the basic composition of water-soluble pitch’s framework. It was found that pitch was soluble in alkaline aqueous solution can be explained by elemental analysis combined with infrared spectroscopy, and fluorescence spectrum combined with Yen-Mullins model gave the main structure information from a microcosmic view, thus enabling a general method for different properties pitch determination.