Abstract: Sichuan Mengding yellow bud have been fingerprinted by using the liquid chromatography-time-of-flight mass spectrometry(LC-TOF/MS)and quantitatively determined its major water-soluble constituents for the purpose of providing theoretical evidence for the identification of Sichuan Mengding yellow bud.Used 24 samples of Mengding yellow buds as experimental materials,gradient elution(phase A was 0.1% formic acid solution and phase B was acetonitrile)was used. Column temperature was 30 ℃,detection wavelength was 278 nm,flow rate was 0.2 mL/min.The LC-TOF/MS fingerprint of Mengding yellow bud was established and cluster analysis was performed to determine the common chromatographic peaks.24 samples of Mengding yellow buds had 16 common chromatographic peaks,and 9 compounds were identified,namely GC(gallocatechin),EGC(epigallocatechin),CAF(caffeine),C(catechin),EC(epicatechin),EGCG(epigallocatechin gallate),GCG(gallocatechin gallate),ECG(epicatechin gallate)and CG(catechin gallate). Quantitative analysis showed the content of GC and EGC in the yellow buds of Mengding yellow bud without piling fermenting process was low,and the content of EGCG and ECG was high,while the content of EGCG in Mengding yellow bud fried with stale tea was low. Factor analysis showed that 14 quality components were combined into 4 common factors.The characteristic values of the first four common factors were greater than 1 and the cumulative contribution rate was 80.44%.The main representative indicators were catechins,caffeine,proteins and sugars.In addition,when the critical value was less than 20,the cluster analysis divided 24 samples into 4 categories.According to the constructed LC-TOF/MS fingerprint of Mengding yellow bud,the Mengding yellow bud from different processes can be identified and evaluated.