A combined ecological floating bed device relates to a combined ecological floating bed device for in-situ purification of polluted water of rivers and lakes, comprising an anchoring rod (2), a fixing rotary shafts (3), a connecting rod (4), a fixing rod (5), a floating body (6), bio-net filler (7) and aquatic plants (8). The floating body (6) is fixedly connected with the fixing rod (5) which is movably connected with the connecting rod (4) and anchoring rod (2) through two fixing rotary shafts (3), the anchoring rod (2) is fixedly connected with a revetment (1), and the floating body (6) is provided with the bio-net filler (7) thereunder and aquatic plants (8), such as iris pseudacorus, scirpus tabernaemontani, canna, torilisjaponica and vetiver, thereon. The invention has the characteristics of simple structure, convenient installation and management, good effect of purifying water, strong stream shock resistance, automatic elevation along with the water level change, no influence to the safety of river channel navigation and the like, thus being very suitable for the in-situ purification of natural river channels, lakes and scenic waters.