A cage for catching freshwater shrimps on the water surface of a large ditch comprises a cage framework, wherein the cage framework is formed by welding steel bar stand columns; the outer side surface of the cage framework is wrapped with a mesh wall to form a cage body; the cage body is square; four shrimp inlets are formed in mesh walls at the front end and on two side surfaces of the cage body; steel bar inverted whiskers are mounted on the four shrimp inlets and fixed by the mesh walls; an interlayer wall is arranged in an inner cavity in the rear part of the cage body; a shrimp storage cabin inlet is formed in the interlayer wall; shrimp inlet steel bar inverted whiskers are mounted on the shrimp storage cabin inlet; a shrimp storage cabin is connected to the rear part of the interlayer wall; a rope hanging nose and a shrimp getting door are arranged on two sides of the top of the shrimp storage cabin respectively; one end of the shrimp getting door is fixed by a movable hinge, and the other end of the shrimp getting door is connected with a door hook; the shrimp getting door can be opened or closed upwards and downwards under the action of the door hook; and a shrimp trapping bag is arranged in a front inner cavity of the cage body and fixed by shrimp trapping bag pull ropes.