There are two types of insulin pens commonly used in clinical practice: 1) pre-filled insulin pens, which means that the solution and insulin are connected together and are disposable insulin pens, and the entire pen can be discarded directly after the solution is used up; 2) insulin pens that can replace the insulin solution, and this kind of pen can discard the empty insulin cartridge after the insulin is used up and replace it with a new insulin cartridge to continue using. Before installation, you should carefully check whether the refill is intact, whether there are cracks, whether there is any abnormality in the color and properties of the liquid in the refill, determine that there is no error and then twist open the refill frame to load the refill, disinfect the rubber at the front end with 75% alcohol, take out the insulin needle and open the package, tighten the needle clockwise, then perform the exhaust operation, you can adjust the dose by twisting the spin wave 2-6 units for exhaust, when there is insulin overflow from the needle It indicates that the drive rod has been completely contacted with the refill and the air bubbles in the refill have been completely discharged, then you can start to inject insulin. When injecting insulin, sterilize the injection site first, enter the needle vertically, and after the injection is completed, the needle needs to be left in the skin for 10 seconds before pulling out.