Monkey cerebral cortex,an important part in the brain to control action and thought activities,is mainly composed of grey matter and nerve cell. In the present paper,the in situ Raman spectra of the cerebral cortex of the birth,teenage and aged monkeys were achieved for the first time. The results show that the Raman spectra for the different age monkey cerebral cortex exhibit most obvious changes in the regions of 1 000-1 400 and 2 800-3 000 cm-1. With monkey growing up,the relative intensities of the Raman bands at 1 313 and 2 885 cm-1 mainly assigned to CH2 chain vibrational mode of lipid become stronger and stronger whereas the relative intensities of the Raman bands at 1 338 and 2 932 cm-1 mainly assigned to CH3 chain vibrational mode of protein become weaker and weaker. In addition,the two new Raman bands at 1 296 and 2 850 cm-1 are only observed in the aged monkey cerebral cortex,therefore,the two bands can be considered as a character or “marker” to differentiate the caducity degree with monkey growth. In order to further explore the changes,the relative intensity ratios of the Raman band at 1 313 cm-1 to that at 1 338 cm-1 and the Raman band at 2 885 cm-1 to that at 2 932 cm-1,I1 313/I1 338 and I2 885/I2 932,which are the lipid-to-protein ratios,are introduced to denote the degree of the lipid content. The results show that the relative intensity ratios increase significantly with monkey growth,namely,the lipid content in the cerebral cortex increases greatly with monkey growth. So,the authors can deduce that the overmuch lipid is an important cause to induce the caducity. Therefore,the results will be a powerful assistance and valuable parameter to study the order of life growth and diagnose diseases.