Infrared Spectroscopy (IR) integrated with two dimensional correlation infrared spectroscopy (2DCOS IR) was employed to rapidly discriminate Dendrobium loddigesii Rolfes (DR) from different regions and harvesting periods. The results showed that the IR peaks around 1 035, 1 051, 1 078, 1 156, 1 500, 1 511 and 1 736 cm-1 had perceptible differences among DRs from different regions, indicating that different DRs containing remarkable different compositions and contents of polysaccharides, ketones and esters. 2DCOS IR spectra of DRs from Vietnam, Yunnan, Guangxi, Guizhou each had seven, eight, eight, nine auto peaks, respectively; furthermore, DRs from Guagnxi had the strongest peak in 1 220 cm-1, which was distinguish to those of other DRs (980 cm-1). In the IR spectra of DRs from different harvest seasons, the wave number of key peaks in (1 034～1 023)cm-1, the wave number of minor peaks in (1 617±4)cm-1, as well as the presence of peaks in 1 078(1 076, 1 079)cm-1, showed obvious periodic changes with the seasons, which indicated the accumulation of polysaccharides and ketones from DRs displayed an evident periodic variability discipline. The application of FTIR in DRs could facilitate acquiring their growth conditions, composition and content changes, which would be significant in rational exploitations and utilizations of DR.