And pain of patient is relieved

The utility model discloses a blood sampling pen capable of relieving pain of a patient. The pen comprises a pen cap, a pen body and a tail rod, an ejection device is arranged in the pen body; the ejection device comprises an ejection rod, a percussion spring, an ejection cavity, a button, a spring sleeve, a reset spring and a clamping sleeve. The button touches and presses to release the clampingand locking structure; the ejection rod is triggered to drive the blood taking needle to axially move forwards to puncture the skin; a circle of convex ring is arranged on a rod body at the front endof a cantilever of the ejection rod; the outer diameter formed by the convex ring is higher than the highest part of the cantilever; the inner diameter of the axial movement section of the convex ring on the front section of the ejection cavity is larger than that of the rear section of the ejection cavity, the convex ring is in micro-clearance fit with the inner wall of the ejection cavity by 0.02-0.25 mm, the stability