Using differential balance, the thermalspectrogram of roots, stems andleaves in three stages of growth and development of wheet is analysed.The trigonometry figure composed of the ratios of oxygen to heat forwheet shows the relationshiop for wheet,it is found that a tangent valueof one angle is negotively related to yield per plant,and the sum of averageenergy for activation positively with ultimate yield.It is thought that it ispossible to use the two values as new criterions for wheet breeding.Althoughthe values cannot indicate substantial meaning,it could demonstrate theultimate state of yield from the relationship among root,stem and leavesof wheet,which provides basis for directional cultivation and breeding.The use of the criterions not only shorten the period to breed but alsoexpand the range for application of the"differential balance".