A bone tumor biopsy puncture auxiliary device effectively increases the function of determining the knife feeding direction of a puncture needle and a scalpel and comprises a frame, a first rotating frame is arranged on the left side of the frame, a second rotating frame is arranged on the right side of the frame, a positioning box is arranged in the frame, and a positioning gooseneck pipe is arranged on the upper side of the positioning box. Fixed gooseneck pipes are arranged on the left side and the right side of a positioning gooseneck pipe, a fixing mechanism is arranged on the upper sides of the fixed gooseneck pipes, a positioning frame is arranged on the upper side of the positioning gooseneck pipe, a fixing frame is arranged on the front side of the positioning frame, a positioning disc is arranged in the fixing frame, a rotating positioning disc is arranged in the positioning disc, and a needle passage positioning disc is arranged in the rotating positioning disc. The fixing device is simple in structure and ingenious in conception, the aim of fixing limbs of a patient is effectively achieved through the design, the risk of local diffusion of cancer cells is reduced, the aim of positioning and fixing a needle passage is achieved, the function of protecting the puncture position of the patient is added, and the function of color contrast is added.