The main factors causing plateau reaction are oxygen deficiency, low air pressure and cold. 1. Lack of oxygen: Oxygen in plateau area is relatively thin, when people living in the plain area first arrive at plateau area, their bodies will be difficult to adapt to the sudden decrease of oxygen, and the decrease of blood oxygen concentration will induce a series of symptoms such as chest tightness, asthma, headache, and so on. 2. Low air pressure: the air pressure in plateau area is relatively low, which will further reduce the partial pressure of oxygen in the alveoli, so that the gas exchange in the alveoli, hemoglobin oxygen transport and oxygenated hemoglobin in the tissues to release oxygen is affected. The whole body is in a state of insufficient oxygen supply, and the nervous system is particularly sensitive to hypoxia, so there will be a plateau reaction mainly headache. 3. Cold: the plateau area is at a higher altitude, the temperature is relatively low, the temperature difference between day and night is relatively large, the plateau area due to the lowering of the temperature, the human body will be cold, the muscle will increase the heat production, oxygen consumption further increase, but also aggravate the reaction of hypoxia. And the first time into the plateau area people can not adapt, it is easy to appear cold, aggravate plateau reaction.