The specific operation methods and steps of intravenous needle infusion include selecting blood vessels, tying tourniquet, puncture and so on. 1. Selection of blood vessels: When performing intravenous infusion, attention should be paid to the selection of suitable blood vessels, it is generally recommended to select the upper limb is better than the lower limb, because the upper limb blood flow rate is faster and does not affect the patient’s activities out of bed, and the left hand is better than the right hand, because most of the right hand is the main hand. 2. Tie a tourniquet: after choosing the appropriate blood vessel, a tourniquet can be tied according to the routine, so that the selected blood vessel can be exposed more obviously, which is more conducive to needling. 3. Puncture: the blood vessels can be sterilized after puncture, pay attention to the alignment of the blood vessels, the angle of the needle should be greater than 30 degrees, the tip of the needle into the blood vessels and then reduce the angle of the blood vessel puncture, along the blood vessels along the needle, after the return of blood into the trocar can be placed. Intravenous needle infusion should pay attention to the specific operation method, it is recommended to find professional medical personnel to operate, to avoid puncture skewed phenomenon.