The invention relates to the field of surgical tools, in particular to a cartilago costalis support shaping knife. The cartilago costalis support shaping knife comprises an adjusting frame and two blades, the two blades are parallelly arranged in the adjusting frame and are slidably arranged on the adjusting frame through slidable parts, the blades are clamped to the slidable parts in a removablemode, and scales are arranged on the side, where the slidable parts are installed, of the adjusting frame. The cartilago costalis is placed in the adjusting frame, and the adjusting frame to fixedly clamp the cartilago costalis; the slidable parts are adjusted to move the blades to the needed scale, and when the blades slide into the slidable parts, the cartilago costalis sheet with a specific length can be cut; the cartilago costalis sheet rotates by 90 degrees on the Y axis, the slidable parts are adjusted, and the cartilago costalis sheet with a specific width is cut; the cartilago costalissheet rotates by 90 degrees on the Z axis, blade grooves are adjusted, and the cartilago costalis sheet with a specific height is cut. The cartilago costalis with needed parameters can be precisely cut, the cartilago costalis support prototype is prepared, and time is saved for fine engraving in the later period; the cartilago costalis support shaping knife is low in cost, simple in structure, convenient to use and applicable to batch production.