The invention relates to a novel environment-friendly floor drain device. The technical proposal of the invention is as follows: a fixing frame (7) is connected inside an inner cavity of a floor drain body (2); a vertically-arranged guide-rod rail (13) is connected with the middle part of the fixing frame (7); a sealing guide rod (8) is arranged in the guide-rod rail (13) in a sliding manner; the lower end of the sealing guide rod (8) is connected with a sealing plug (10) and the upper end thereof contacts with an inner-end rod (14) of a buoy (5); the inner end of the buoy (5) is movably arranged on the guide-rod rail (13); the buoy (5) appears as a hollow structure and a weight-balancing ball (6) is arranged in the hollow cavity and a certain of stroke is preserved at the cavity bottom surface of the buoy (5) for the left-right rolling of the weight-balancing ball. The invention adopts the weight-balancing variable force manner to realize the permanent and stable sealing; and the automatic opening can be easily realized, the maintenance can be avoided and the use is convenient.