The daytime variation of the heat balance in the secondary oakery has been analyzed in the weather of cloudless and partly cloudiness.The results indicate that daytime changes of the income and outputs of the oakery heat have analogy with the diurnal variation of the receiving solar above the canopy:it is a single wave model.When the net radiation is over 60% of the solar radiation,it supplies the soil heat storage.The expenses of the latent heat and the sensible heat are over 88% of the net radiation in the same moment.