Objective: To compare the differences of the chemical constitutions of Frutus Aurantii Immaturus of different origin Places. Method: By one-dimensional FT-IR spectroscopy

second derivative spectra and two-dimensional related spectral analysis of IR spectra

the features of these spectrum peaks of Frutus Aurantii Immaturus were identified. Result: In one-dimensional map

the raw material of Frutus Aurantii Immaturus from 5 different origins had the similar peak shape among the rang of 400-4 000 cm-1

and 7 common peaks. Frutus Aurantii Immaturus from each origin place had the same chemical content. In the second derivative spectra the characteristic peaks of Frutus Aurantii Immaturus from Yunnan were less and blunter

the more peaks of Frutus Aurantii Immaturus from Jiangsu and Jiangxi were found

and the shapes of peaks were sharp. The two-dimensional related spectral map showed there were obvious differences between the peaks of Frutus Aurantii Immaturus from 5 different origin places. Conclusion: This IR spectra technique can identify Frutus Aurantii Immaturusof different origin places.