The invention discloses a plant ecological floating bed which comprises a floating bed carrier, wherein a solar aeration device is arranged on the carrier; emergent plants are planted on the floating bed carrier; a microbial load bed is arranged below the water surface; the microbial load bed and the floating bed carrier are arranged in parallel through a connecting piece. An emergent plant bed body provided by the invention is made of polystyrene materials and is corrosion-resistant, frostproof, environment-friendly and long in service life; hardy plants are planted on a planting bed, so that an ecological floating bed system can also purify the water in winter. According to the invention, the emergent plants are combined with microorganisms, so as to form a double-treatment system of the emergent plants and the microorganisms, and promote the quick degradation and transformation of pollutants.