Remote sensing mi agery provides vast information about the land surface, and the spatialdistribution of land cover types by classification could be obtained. Moreover, the spectrum of land surface objects is useful to mi prove the accuracy of mi age classification. However, the spectrum of the same objectmay be differentwhen they aremeasured at differentmeasuring scale andwith differentmethod. Forexample, the spectrum ofwinter-wheatextracted from LandsatTM andmeasured in the field are different. So it is mi portant to study the scale effectand scalingmethod on the spectrum at differentmeasuring scale.In this paper, we took thewinterwheatas example, and selected Shunyi region in Beijing as our study area. Firstly the definition of three-scale spectrum was explained, then we analyzed the discrmi ination using the measuring data to highlight the mi portance of the scale transformation of spectrum. The collected data included: fieldmeasured spectrum of leaf and canopy and the hyper-spectrum high-resolution remote sensed mi ageryOMIS, LandsatTM andMODIS data. We compared the winter-wheat spectrums and calculated the slope of“red-edge”at differentmeasuring scales. We also studied the scaling-up method of the spectrum, and the physicalmodel (SAILH) and statisticalmodel (Linearmixing model) were used to describe the relationship between the spectrum at differentmeasuring scales. SAILH is a typical radiation transfermode,l which can be used to smi ulate the canopy spectrum by taking the leaf spectrum, some structural parameters and environmental variables as inputs. In this expermi ent, the input parameters were acquired with high accuracy, so the error of smi ulation result is very smal:l 8. 45%. Linear mixing model was used to describe the relationship between endmember spectrum and pixel spectrum. The resolution ofMODIS mi agery (visible and infrared bands) is 250m, whichwas taken as pixel spectrum, and the endmember one can be gotbymultiplemethods, herewe adopt twomethods: Broadmanmethod fromMODIS mi agery and aggregation one from TM mi agery. The unmixing results were compared and analyzed, and the linearmixingmodelwas validated.Through the spectrum data in the study area, the winter-wheat spectrum of lea,f canopy and OMIS mi agery is\ndifferent and the character reflecting the plantgrowing status is also varied. As for the scalingmethod, we found statistical models and physicalmodels are fit on the three research scales respectively. However, the endmember selectingmethod\nfrom the mi agery alsoneedsmore mi provement, andmore statisticalmodelsorcouplingphysicalmodels should be explored\nin the furtherwork.