Moisture and temperature are the main factors that affect the respiration of grain. These two elements are not isolated, but restrict each other. When the moisture content of the grain is low, temperature has little effect on respiration; when the moisture content increased, the change in respiration intensity caused by temperature is very intense. According to the experiment, when the moisture content of grain is 18-23% and the temperature is 50 ℃ to -5 ℃, the respiration suddenly rises and then suddenly weakens. However, if the grains whose moisture content is 14-16% has been putted at the same temperature for few days, there is almost no change of respiration.