The invention discloses a minimally invasive scalpel manufacturing method which is based on a round slotting tool, a contracting chuck, an ejection rod and a minimally invasive scalpel. A plurality of first line through grooves and a plurality of second line through grooves are formed in the round slotting tool in the axial direction in parallel. The first line through grooves extend from one end face of the round slotting tool to the middle of the round slotting tool to form a plurality of first elastic blades. The second line through grooves extend from the other end face of the round scalpel to the middle of the round slotting tool to form a plurality of second elastic blades. The manufacturing method includes the following steps: step1 utilizing the contracting chuck to clamp the round slotting tool to form a deformed round slotting tool; step2 arranging the deformed round slotting tool in the step1 into a through hole of an outer aluminum pipe sleeve; step3 placing the ejection rod into the through hole of the outer aluminum pipe sleeve to push the ejection rod to drive the deformed round slotting tool to move. By means of the manufacturing method, small protruding points can be removed cleanly and smoothly, the round slotting tool have certain elastic force and can be in contact with the inner wall of an aluminum pipe at any time, and the small protruding points on the inner wall can be removed to the largest extent.