In the aquatic environment, colloids are ubiquitous and have small particle size, large specific surface areas and multiple adsorption sites. Colloids can adsorb the organic contaminants, and change and control their environmental behavior. Perfluorinated compounds (PFCs) may be associated with the colloids in surface water to form effects of combined pollution due to non-hydrophilic and non-lipophilic properties and persistence of PFCs. In this paper, river-lake system of a national ecological demonstration area was selected as the study area, spatial distribution characteristics and colloidal adsorption potential for 4 typical PFCs including pentadecafluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFDA) were investigated in the traditionally dissolved phase to assess their ecological risk level. The main results were as follows:(1) All four PFCs were detected in the traditionally dissolved phase and colloidal phase, with the detection rate of 78.8%-100% and the total concentrations of 12.5-92.1 ng/L and 5.4-49.9 ng/L, respectively. In the traditional dissolved phase and colloidal phase, PFOA are the main PFCs. The contribution rates of PFOA to PFCs were more than 65%, followed by PFOS, PFNA, PFDA. (2) From the medium distribution, colloids are an important "sink" of PFCs, average adsorption contribution rates of colloids to PFCs are between 42.6% and 66.1%. PFDA showed the greatest adsorption potential, with an average absorption contribution rate of 66.1%, followed by PFNA (53.5%), PFOA (47.0%) and PFOS (42.6%). The adsorption contribution rate of colloids to PFCs was significantly positive correlation with the lgK_OW of PFCs. (3) In terms of spatial distribution, residential areas have the highest pollution levels, with an average concentration of 71.2 ng/L, followed by Qinhu Wetland Park (43.3 ng/L). In industrial, agricultural and urban areas, PFCs have comparable pollution levels, with average concentrations between 30 ng/L and 40 ng/L. Aquaculture area showed the lowest pollution levels. (4) Using risk quotient (RQ) and water quality benchmark to assess the water environment risk, we found that the aquatic organisms in 58% of sampling sites were in low-risk state caused by PFOS, mainly located in industrial areas and residential areas. And PFOS pollution levels in all the sampling sites were higher than the annual average environmental quality standard (0.65 ng/L) setting by the European Commission for PFOS in freshwater environments, which is lower than the maximum acceptable concentration environmental quality standard of 36 μg/L. Chronic ecological risks caused by long-term occurrence of PFOS in aquatic environment should not be ignored.