In order to explore an intelligent, non-destructive method for detecting the boundary of melanoma. In this study, a.ber optic spectrometer (FOS) system combined an integrated structure with an automatic software was developed and em-ployed for distinguishing the skin pigmentation. After collecting scattering spectrum from sample, a correlation test will be performed with standard spectrum. The system will automatically give a judgment based on the correlation coe.cient. The feasibility of the FOS system for rapid and intelligent detecting the pigmentation was.rst tested by an ex vivo experiment. A tricolor agar phantom stained by red, green and blue inks could be identified by the FOS system with 96% accuracy. Further-more, a melanoma mouse model induced by subcutaneous injection of ink was examined by the FOS system in vivo. There were signi.cant di.erences in spectrum between the ink-injection region and the normal region. Comparison with the stan-dard spectrum of injected ink, the correlation coefficient of the ink injection area was 0.83±0.07, while the normal tissue was 0.18±0.05. The boundary of the ink pigmentation area in the skin could be clearly identi.ed from the correlation coe.-cient map. Both the ex vivo and in vivo experiment demonstrated the FOS system could identify pigmentation with high sen-sitivity and speci.city, and indicated its great potential to be used in the clinical diagnosis of melanoma.