The invention discloses a method for turning middle and small thin-wall element, wherein the invention uses auxiliary clamper on general turning machine, first based on the outer diameter of element, produces a slim sheath with same diameter and middle slim as auxiliary clamper, machines the blank of object element, then puts the draw-in gear into the inner hole of slim sheath, puts them together into three-claw positioning clamping disc of turning machine, clamping and machining roughly and finely, and since the invention uses slim sheath as auxiliary clamper, the long-disc claw can obtain uniform dispersed clamping force on the surface of object element, to reduce unit clamping force, reduce vibration and deformation or the like. And the invention improves efficiency via transferring thin-wall element on three-claw automatic positioning clamping disc.