Fifteen honey samples which found to contain no protein from 120 specimens were further investigated by element analyzer-isotope ratio mass spectrometry, liquid chromatography-isotope ratio mass spectrometry and liquid chromatography, the protein components in the honey samples were detected. It was found that adulteration existed in all the tested fifteen samples. The samples were found to be adulterated by C-4 plant hydrolyzate, C-3 plant hydrolyzate or C-3 plant high fructose corn syrup.