The formula for infusion calculation, commonly used, is the amount of fluid input per hour, which is equal to the number of drops of the infusion set multiplied by four. For example, the drip rate of the infusion set is twenty-five drops per minute, which is converted into the amount of liquid, that is, one hundred milliliters per hour is input into the body, and if it is five hundred milliliters of liquid, it will take five hours to finish the infusion. At the same time, the time of infusion, depending on the condition, and the nature of the input fluid to decide. If the patient is in hypotensive shock, hypovolemic shock, traumatic hemorrhage to the hospital, the amount of fluid input should be very fast at the beginning, the purpose is to expand the volume and maintain the patient’s blood volume. If the input is a fatty milk preparation, it will affect the patient’s blood vessels and may lead to fat overload syndrome after fast infusion because the concentration is relatively large, so the speed should be slower.