Woolen　textile　industry　produces　enormous　wastewater　(WTIW)　with　high　pollution　loads,　and　needs　to　be　treated　by　wastewater　treatment　stations　(WWTS)　before　centralized　treatment.　However,　WTIW　effluent　still　contains　many　biorefractory　and　toxic　substances;　thus,　comprehensive　understandings　of　dissolved　organic　matter　(DOM)　of　WTIW　and　its　transformation　are　essential.　In　this　study,　total　quantity　indices,　size　exclusion　chromatography,　spectral　methods,　and　Fourier　transform　ion　cyclotron　resonance　mass　spectrometry　(FTICR　MS)　were　used　for　comprehensively　characterizing　DOM　and　its　transformation　during　full-scale　treatments,　including　influent,　regulation　pool　(RP),　flotation　pool　(FP),　up-flow　anaerobic　sludge　bed　(UA),　anaerobic/oxic　(AO)　and　effluent.　DOM　in　influent　featured　a　large　molecular　weight　(5–17　kDa),　toxicity　(0.201　HgCl2　mg/L),　and　a　protein　content　of　338　mg　C/L.　FP　largely　removed　5–17　kDa　DOM　with　the　formation　of　0.45–5　kDa　DOM.　UA　and　AO　removed　698　and　2042　chemicals,　respectively,　which　were　primarily　saturated　components　(H/C　＞　1.5);　however,　both　UA　and　AO　contributed　to　the　formation　of　741　and　1378　stable　chemicals,　respectively.　Good　correlations　were　found　among　water　quality　indices　and　spectral/molecular　indices.　Our　study　reveals　the　molecular　composition　and　transformation　of　WTIW　DOM　during　treatments　and　encourages　the　optimization　of　the　employed　processes　in　WWTS.　©　2023