In order to obtain 240 cases of the surface Fourier transform infrared (FTIR) spectra of normal human thyroid gland, 120 healthy volunteers were enrolled in this study and scanned by using two mid-infrared optical fibers equipped with an attenuated total reflectance (ATR) to probe through the skin of two lobes of thyroid gland. Then whether there were differences between the surface FTIR spectra of the right lobe and that of the left part of the normal human thyroid gland was explored by comparing the 35 variables of 12 bands, including peak positions, relative intensity ratios and full width at half maximum of FTIR spectrums. Also the spectra characteristics of unique absorbent bands that represent changes of structure and quantity of variance biochemical substances such as nucleic acids, proteins and carbohydrates were illustrated. Results indicated that the surface FTIR spectra of the right part and that of the left part of the normal human thyroid gland were generally coincided, with statistically significant differences in four spectrum parameters, includingF1 640, P2 920, P1 040 and I2 920/I1 460. A series of data about the 90% normal reference range of the unique spectrum parameters in the surface FTIR spectra of normal human thyroid gland was gained, and a standard average infrared spectrogram which can fully represent the basic features of normal human thyroid gland was plotted. The conclusions above could be used as a reference for clinical diagnosis of thyroid diseases with FTIR spectroscopy.