Surface enhanced Raman spectroscopy (SERS) has shown the advantage of detecting low concentration biofluids presently. Saliva SERS of 21 lung cancer patients and 22 normal people were measured and differentiated in the present paper. Intensities of most peaks of lung cancer patients are weaker than that of normal people, while some stronger but with a small change rate. Those peaks were assigned to proteins and nucleic acids which indicate a corresponding decrease of those substances in saliva. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to deduce and discriminate the two groups of data, resulting in accuracy, sensitivity, and specificity being 84%, 94%, and 81%, respectively.