The invention discloses an undercurrent zone organism sampling device which mainly comprises an air cylinder and a sampling tube. The air cylinder comprises a cylinder, a manual lever, a piston rod, an upper piston valve and a lower piston valve; a water outlet is formed in the upper end of the cylinder; the manual lever is arranged outside the cylinder, the piston rod is arranged inside the cylinder, and the manual lever is connected with the piston rod by connecting shafts; the piston rod is connected with the upper piston valve by a piston pin; a piston sealing ring is arranged at the bottom of the upper piston valve; the lower piston valve is arranged at the bottom of the cylinder; the sampling tube is connected with the cylinder by bolts; a sharp end is arranged at the bottom of the sampling tube; water via holes are formed in the side, which is close to the sharp end, of the sampling tube, and a filter screen wraps the inner tube wall of the sampling tube and corresponds to the water via holes. The undercurrent zone organism sampling device has the advantages that undercurrent zone organisms can be sampled by the undercurrent zone organism sampling device without being disturbed, categories and composition of the undercurrent zone organisms further can be analyzed and discriminated, and the undercurrent zone organism sampling device is simple in integral structure and ingenious in conception.