The invention discloses an unmanned aerial vehicle remote sensing-based wave and floating body movement forecasting system, and belongs to the technical field of ships and marine engineering. A shipborne unmanned aerial vehicle is used to obtain a ship's periphery distant wave flow field, and the information on the picture is analyzed and inversely deduced to obtain wave elevation information; thewave elevation information obtained by the unmanned aerial vehicle is processed, and an irregular wave surface is decomposed into superposition of a plurality of regular waves; the moments of all monochromatic waves reaching the ship are calculated according to wave propagation models, the proportion of the monochromatic waves, reaching the ship at every moment, in total monochromatic waves is calculated, and forecasting is carried out if the proportion is higher than a preset threshold; and all monochromatic waves generate wave surfaces according to a predetermined wave model, the wave surfaces are the forecast wave surfaces, and the movement of a floating body is calculated through RAO, a pulse response function and other fast algorithms. The system provides long-period accurate wave field information and self movement forecasting information for offshore structures and engineering work, and improves the working efficiency.