In-situ analysis the chemical composition of tibial articular cartilage of female Hartley guinea pigs with Fourier transform infrared (FTIR) microspectroscopy was conducted. The infrared spectrum survey consists of three ages (1 months, 2 months and 3 months)and three cartilage layers(surface, middle and deep). The results demonstrated that with ages increasing, the peak positions of main absorbance bands in surface and middle shifted to a lower wavenumber, and in deep they shifted to a lower wavenumber first, then shifted to a higher wavenumber. Infrared spectrum character of collagen, nucleic acid and proteoglycan were compared and analyzed, The ratios of I1 657/I1 548, I1 074/I1 548 and I1 074/I1 237 tend to decrease with ages increasing in surface and middle. However, the ratios at 2 months are less than other ages in deep. These results are consistent with the regular pattern of cartilage ingredient change in different degradation stage, while the tibial platform images created by microscopic spectral imaging technology is highly compliant with pathology description. The authors’ primary result illustrated that FTIR microspectroscopy can be used for in-situ analysis of molecular constituents of different levels cartilages. The molecular information obtained from the study is important for understanding the pathogenesis of cartilage diseases.