2-year-old children can’t draw blood when checking hepatitis B antibody, which may be caused by factors such as fine blood vessels, obesity, and unskilled operation of blood collection personnel, etc. This problem can be improved by strengthening nutrition, proper exercise, or choosing experienced health care workers. 1. Fine blood vessels: Generally speaking, the blood vessels of 2-year-old children are relatively fine, and the lack of plumpness of blood vessels can easily lead to puncture failure. This situation can be gradually improved by giving the child more fresh fruits and mushrooms, strengthening nutrition and enhancing physical fitness. 2. Obesity: usually fat children, the fat layer is thicker, in this case the child’s blood vessels are deeper, health care workers are not very good for puncture. At this time, you can let the child to carry out appropriate exercise, eat less greasy fried food, reduce weight. 3. Incompetent operation: If the blood collector is not skillful in operation and does not have a good grasp of the child’s blood vessel puncture method, it may also lead to failure to draw blood. In this case, it is recommended to find an experienced staff to collect blood for 2-year-old children. Clinical dehydration and low blood volume may also lead to failure to draw blood. At this time, parents are advised to ask the doctor in detail to find out the specific reason why the child cannot draw blood and then make improvements.