The invention provides a detection system and method for the deposition mass of an aerially applied pesticide. The detection system comprises an aerial sprinkling apparatus, a droplet collecting apparatus, a spectrum acquisition apparatus and a droplet deposition characteristic analysis apparatus, wherein the aerial sprinkling apparatus is filled with a pesticide application solution mixed with a fluorescent tracer and used for sprinkling the pesticide application solution to a preset area; the droplet collecting apparatus is a rollable continuous band-shaped medium laid in the preset area, having preset width and free of fluorescent effect, and the continuous band-shaped medium is used for collecting the pesticide application solution sprinkled by the aerial sprinkling apparatus; the spectrum acquisition apparatus is used for spectrum acquisition of the continuous band-shaped medium having collected the pesticide application solution; and the droplet deposition characteristic analysis apparatus is used for analyzing spectra acquired by the spectrum acquisition apparatus and calculating the deposition mass of droplet in the preset area. The detection system and method provided by the invention can conveniently acquire the deposition mass of the aerially applied pesticide.