In order to overcome the defects in the prior art, the invention provides a water body sampling device capable of realizing stratified sampling, solves the problem that errors are generated during subsequent water sample analysis due to mutual pollution of water body samples during traditional water body collection, and adopts the technical scheme that the water body sampling device comprises a barrel body, and a plurality of flat plates are fixed on the barrel body; a driving shaft, push rods and rotating shafts are arranged at the bottom of the barrel body; an incomplete bevel gear is arranged on the driving shaft, an incomplete circular gear is sleeved on the driving shaft, teeth are arranged on the push rod and meshed with the incomplete circular gear, a bevel gear is arranged at the lower end of the rotating shaft, a sampling bottle is arranged in the barrel body, a through hole capable of communicating with the outside is formed in the side wall of the barrel body, a first through hole is formed in the first-layer plate, and a second through hole is formed in the second-layer plate; a sealing bottle cover is arranged on the second through hole; the water body sampling deviceis novel in conception, the water sampling device is completely placed in water for direct water body collection and respective sealing, the problem of mutual pollution of water samples during multilayer water sample collection is avoided, and the water body sampling device is ingenious in structure and convenient to use.