Abstract: The low temperature phenomena of wheat and mungbean canopy were studied. The results show that the germplasm materials in wheat and mungbean have a persistent low canopy temperature, and their temperature type of the materials does not change whatever year and whatever kind of weather. Some important biological traits of the low temperature materials, i. e. the functional periods of the leaves, chlorophyll contents, protein nitrogen contents, SOD activities and net photosynthetic rates, are more excellent than those of the high temperature germplasm materials and all these can provide a solid ecological and physiologic basis to obtain high and stable yield. The low temperature materials in wheat and mungbean have a common characteristic with the excellent biological traits though the blood relationship of wheat and mungbean is very far, which is beneficial to the improvement of crop's productivity.