Longkou brown coal was oxidized by H2O2 at 40 degreesC for 10 h. Water-phase fraction from the reaction mixture was extracted with chloroform to afford chloroform-soluble, chloroform-insoluble but water soluble (CIWS) and solid subfractions. A series of heteroatom(s)-containing organic compounds were detected with GC/MS from the CIWS subfraction. The heteroatoms included O, N, S, and Cl.