Functional traits variations are not only constrained by ontogeny but also affected by specific environmental factors.In this paper, the sources and structures of 11 functional traits in a macrophyte species Potamogeton maackianus are studied.We measured these traits from 681 individuals across five ecological scales:lake, transect, sample depth, sample area and individual.The results showed that:1) A great high trait variation (0.40-1.21) was observed within species.2) The five ecological scales had a great influence on the structures of trait variations, depending on the selected specific trait.These measured traits were most responsive to individual scale, while stem mass and internode number were largely affected by environmental factors at scales of lake, transect and depth stratus.3) Ontogenetic variance of these traits ranged from 5% to 76%, and was non-negligible at each ecological scale.