The invention discloses a blood drawing auxiliary device for departments of hematopathology and a method for applying the blood drawing auxiliary device. The blood drawing auxiliary device comprises atank. The front end surface and the rear end surface of the tank are communicated with each other, a second line roller is fixedly connected with the rear end surface of a first line roller, a thirdline roller is fixedly connected with the side, which is far away from the first line roller, of the second line roller, a rotary rod is fixedly connected with a certain side of each of the first lineroller and the third line roller, the certain side of the first line roller and the certain side of the third line roller are far away from the second line roller, the two rotary rods are positionedat the same horizontal altitude, a support plate is movably connected with the end, which is far away from the second line roller, of each rotary rod and is fixedly connected to the top of the tank, aflat spiral spring is arranged on a certain side of each of the first line roller and the third line roller, the certain side of the first line roller and the certain side of the third line roller are far away from the second line roller, the top of the end, which is far away from a pedal, of a third rope penetrates the top of the tank, and the third rope is wound on the third line roller. The blood drawing auxiliary device for the departments of hematopathology and the method have the advantages of high efficiency, simplicity in operation and the like.