Abstract:　Three-dimensional　fluorescence　spectrum　technology　(EEMs)　and　parallel　factor　analysis　(PARAFAC)　were　applied　to　study　the　space-time　distribution　characteristics　and　sources　of　the　dissolved　organic　matter　(DOM)　in　water　of　Cihu　Lake,　in　order　to　provide　references　for　the　treatment　of　urban　eutrophic　lakes.　The　results　show　that　in　Cihu　Lake,　DOM　mainly　consisted　of　terrestrial　humic-like　component　C1　(340/430　nm),　unknown　humic-like　component　C2　(390/480　nm),　protein-like　component　C3　(290/350　nm)　and　the　self-generated　tryptophan　component　C4　(280/330　nm).　Among　them,　C1　was　the　largest　contribution　to　DOM　of　Cihu　Lake,　and　C4　was　the　smallest.　There　were　temporal　and　spatial　differences　between　the　four　components　of　the　Cihu　Lake.　The　maximum　fluorescence　value　(Fmax)　of　each　component　was　higher　in　summer　and　autumn,　lower　in　winter　and　spring.　The　most　obvious　component　was　C1,　followed　by　C3.　In　terms　of　spatial　distribution,　the　Fmax　value　was　higher　in　the　area　which　was　close　to　residential　areas,　and　component　C1　changed　most　obviously.　(3)　The　components　of　DOM　in　Cihu　Lake　was　mainly　derived　from　different　kinds　of　humus,　followed　by　endogenous　protein-like　substances　degraded　by　microorganisms.　(4)　There　was　a　significant　positive　correlation　between　components　C1,　C2　and　C3　in　Cihu　Lake,　which　indicate　that　they　had　homology.　(5)　It　showed　a　strong　positive　correlation　with　Chl-a　conceatration　in　the　absorption　coefficient　of　a350,　which　indicate　that　the　fluorescence　absorption　property　of　DOM　was　closely　related　to　phytoplankton.　©　2020,　China　Environmental　Science　Press.　All　rights　reserved.