Composition structure for ecologycal lake

According to the present invention, provided are an ecological lake constructing structure and a method for constructing an ecological lake using the same. The structure to construct an ecological lake (100) where a wetland (110) is included comprises a main dam (200) blocking a flow of a river; an overflow reservoir (300) which is formed before the main dam in the flowing direction of the river and maintains a certain water level of the ecological lake; and an embankment for wetland formation formed around the wetland, which is formed in an area of the ecological lake (100), in order to prevent the wetland (110) from being submerged at a higher water level than the water level (301) of the overflow reservoir (300) as well as in order for the wetland (110) to maintain a certain water level.