Abstract: Objective: To identify oral microorganisms extracted from healthy young people by Fourier transform infrared spectroscopy (FT-IR). Methods: FT-IR fingerprint data of 50 typical strains, which were extracted from oral cavity of 30 healthy people, were analyzed by a series of methods like averaging, the first derivative, and vector normalization. They were analyzed by the cluster methods and compared with the standard strains. Results: Isolated strains were easily to be compared with the standard strains in the characteristic spectrum area at 3000-2800, 1500-1400, and 1200-900cm^-1. Conclusion: As a technique which was accurate, fast, convenient, and time-effect, FT-IR was a reliable method for preliminary evaluation of oral microorganisms. It has guiding significance in establishing an early warning system for diseases caused by oral microorganisms.

Key words: FT-IR , Oral microorganisms