The invention relates to an ecological-floating-bed-based water body ecological restoration method which comprises the following steps: 1) establishing an ecological floating bed, adding biological activated carbon into each growing basket, and suspending rope-shaped carbon fiber ecological grass on the bottom of the floating bed; 2) growing emerging plants in a first aquatic plant growing region, wherein the emerging plants are composed of more than two of Canna generalis, Thalia dealbata, Iris wilsonii, calamus, purple loosestrife, bamboo reed, reed, cyperus altrnlifolius and Pontederia corda; growing a floating leaf plant or submerged plant in a second aquatic plant growing region, wherein the floating leaf plant is Ludwigia stipulacea, and the submerged plant is watermilfoil; and 3) reaping: carrying out periodical reaping according to the growth condition of the aquatic plants. The multiple ornamental plants and plant species with higher synergic decontamination capacity are reasonably blended and grown to establish a stable floating bed phytocommunity, thereby enhancing the synergistic actions among organisms, enhancing the restorability of the ecological floating bed for the water ecological environment, effectively enhancing the purifying effect of the ecological floating bed, and having stabler purifying effects.