The invention discloses a collecting device for resected specimens under a gastrointestinal endoscope. The device comprises a base, a sleeve plate is rotationally connected to the left side face of the base, cutter shafts are arranged in four shaft holes formed in the edge of the base, blades are fixed to the right end faces of the cutter shafts, and gears are fixed to the left end faces of the cutter shafts. The collecting device for the resected specimens under the gastrointestinal endoscope is simple in structure, tissue at the specimens is absorbed through a negative pressure pipe, cuttingand separating are conducted through rotation of the blades, the specimen tissue is absorbed in the negative pressure pipe, operation is easy, the position of the negative pressure pipe can be adjusted, the specimen tissue is absorbed conveniently, rotation of the blades is controlled through movement of the negative pressure pipe, swing of the negative pressure pipe and the blades is controlledthrough electromagnets, convenience is brought to operation, cutting of the specimen tissue can be achieved rapidly, the separation effect is good, adhesion does not occur, convenience is brought to extraction, the device is suitable for collection of focus tissue under the gastrointestinal endoscope, and subsequent diagnosis and treatment are facilitated.