The　composition　and　structure　of　dissolved　organic　matter　(DOM)　play　vital　roles　in　the　material　cycle　of　river　ecosystems.　Based　on　ultraviolet-visible　absorption　spectroscopy,　excitation-emission　matrix　fluorescence　spectroscopy,　and　ultrahigh-resolution　electrospray　ionization　Fourier　transform　ion　cyclotron　resonance　mass　spectrometry　technology,　this　study　comprehensively　characterized　the　composition　and　structure　of　DOM　in　the　overlying　water　of　the　Chaobai　River　in　order　to　determine　the　potential　environmental　impact　of　DOM　on　the　water　quality.　The　results　showed　that　the　DOM　content　of　the　overlying　water　in　the　Chaobai　River　was　between　10.94　and　28.13　mg/L.　The　main　DOM　component　of　the　overlying　water　was　humus　(70.94%).　The　relative　abundance　of　CHOS　compounds　in　the　Chaobai　River　was　lower　than　Maozhou　River　(urbanized　river)　and　significantly　higher　than　Xiangxi　Bay　(suburban　river).　In　addition,　the　DOM　composition　and　structure　of　the　overlying　water　were　closely　related　to　anthropogenic　input,　microbial　activity,　and　phytoplankton.　In　particular,　chlorophyll　a　can　indirectly　reflect　fresh　autochthonous　DOM　content　and　composition　in　the　overlying　water.　The　results　of　this　study　further　reveal　the　characteristics　of　suburban　rivers　and　provide　theoretical　basis　and　guidance　for　the　water　quality　evaluation　and　pollution　control　of　the　Chaobai　River　and　other　suburban　rivers　worldwide.