The　composition,　distribution,　and　degradation　of　chromophoric　dissolved　organic　matter　(CDOM)　in　the　lower　reach　and　estuary　of　the　Minjiang　River　were　analyzed　using　fluorescence　excitation-emission　matrices-parallel　factor　analysis　(EEMs-PARAFAC)　and　microbial　and　photochemical　degradation　experiments.　The　results　show　that　there　are　three　types　of　fluorescence　components　in　the　study　area:　humic-like,　tyrosine-like,　and　tryptophan-like.　The　humic-like　components　are　the　main　components　in　the　river　zone,　while　the　protein-like　components　become　dominant　with　increasing　salinity　in　the　estuary.　The　change　of　the　CDOM　abundance　shows　a　notable　spatial　distribution　pattern.　The　absorption　coefficient　a(280)　of　CDOM　is　lower　in　the　river,　increases　after　entering　the　urban　area,　shows　a　decreasing　trend　in　the　suburbs,　and　rapidly　declines　in　the　estuary.　A　conservative　estimate　of　the　contribution　of　the　Fuzhou　urban　area　to　the　CDOM　of　the　Minjiang　River　is　8%.　The　a(280)　in　the　river　is　susceptible　to　microbial　and　photochemical　degradation　and　the　degradation　percentages　are　(28±8)%　and　(44±7)%,　respectively.　The　bioavailability　and　photochemical　reactivity　of　a(280)　are　much　higher　in　the　river　than　in　the　estuary.　The　humic-like,　tyrosine-like,　and　tryptophan-like　components　show　a　higher　photochemical　reactivity　in　the　river,　with　degradation　percentages　of　(75±0.5)%,　(58±21)%,　and　(73±3)%,　respectively.　The　fluorescent　components　are　not　labile　with　respect　to　microbial　degradation　and　humic-like　components　are　accumulated　after　28　days　of　microbial　culture.　©　2019,　Science　Press.　All　right　reserved.