The concentration, speciation and distribution of rare earth elements (REEs) in the suspended particulate matter ( SPM) of Lake Chaohu were studied by inductively coupled plasma mass spectrometry (ICP-MS) after sequential extraction in order to investigate the source of matters in the aquatic environment. The result shows that the total REE concentrations in SPM have a wide range with the value varying between 19. 2-174. 82 mg/kg. These concentrations in the east part of lake were clearly higher than that in the west part of lake. Shale-normalized REEs of residual fraction of SPM show the light REE enrichment pattern in the east part of lake，while it is heavy REE enrichment in the west part of lake. The results indicate that the SPM in the lake Chaohu have different materials source. The solid speciation characteristics of REE in the SPM are also very different from the east part of lake to the west part of lake. The percent of four forms of SPM obey the following order； residual > bound to Fe-Mn oxides >> adsorbed-exchangeable-carbonate (AEC) or bound to organic matter in the east part of lake Chaohu, and Fe-Mn oxides > residual >> AEC or bound to organic matter in the west part of lake Chaohu. It is because the pollution intensity has a decreasing tend from the west part to the east part of the lake. The speciation characteristics of REE in SPM may can as a new indicator of water pollution.