Needle than steel needle pain, the following reasons are common: 1, thicker diameter: the diameter of the needle is obviously thicker than the steel needle, in the venous puncture will lead to local obvious pain; 2, stimulate to the wall of the venous blood: needle placed after the needle is a hose, may stimulate the wall of the venous blood and cause pain, especially in the patient’s hand activities when the symptom is more pronounced; 3, caused by chronic inflammation: the needle left in too long a period of time is likely to cause local chronic inflammation, which leads to pain symptoms; therefore, the needle is more obvious than the steel needle pain symptoms. Too long, it is easy to cause local chronic inflammation, which leads to pain symptoms; therefore, indwelling needle is more obvious than steel needle pain symptoms. The needle can not be left for a long time, otherwise it may produce infection and other risks, so patients should be removed in time to avoid serious pain symptoms. The needle also needs to be carefully placed to minimize damage to blood vessels.