Changes of chemical compositions in Coleus blumei roots under lead (Pb) stress with different concentrations of selenium (Se) treatments (0, 0.1, 0.5, 1.0, 2.5, and 5.0 mM) were analyzed by Fourier transform infrared (FTIR) spectrometry and 2-dimensional FTIR correlation spectroscopy. This was to investigate the spectroscopy differences and microscopic dynamics of chemical functional groups in C. blumei roots under Pb stress with exogenous selenium treatment. The results show that the peak shapes remained basically unchanged in C. blumei roots exposed to Pb stress with different concentrations of Se treatments, and the wave number of the absorption peaks remained stationary. However, there was a significant difference in absorption peak strength, which is influenced by chemical composition. Semiquantitative data indicate that there were obvious differences between the characteristics of the organic functional groups. There were differences between the 2D-FTIR correlation spectra of C. blumei roots in the region of 929-1,800 cm^-1 under Pb stress with different concentrations of Se treatments, which are probably related to differences in chemical composition and structure. The FTIR spectra confirm the presence of various functional groups from the responses to abiotic stresses in the plant, and 2D-FTIR correlation spectroscopy may be a convenient and effective method in the study of plant molecular interactions under environmental stress.