Abstract: Objective:To study transfer rule of caffeine in extraction processing of Ginkgo biloba leaves extracts by an ultra-high performance liquid chromatography-tandem mass spectrometry method. Methods:Chromatographic column was chosen as ACQUITY UPLC BEH C18(2.1 mm×50 mm,2.7 μm). The mobile phase of 0.1% formic acid aqueous solution and 0.1% formic acid acetonitrile was proceeded with gradient elution,at the flow rate of 0.3 mL/min. The chromatographic condition also included sample quantity of 5 μL,column temperature of 30 ℃ and the running time of 5 min. The mass spectra parameters were determined by electrospray ion source(ESI)and multi-reaction monitoring,and the scanning method was positive ion mode. Results:By optimizing the detection method,the recovery was between 95.23% and 102.49%,and the detection limit was 5 μg/kg.The quantitative limit was 15 μg/kg. Conclusion:This UHPLC-MS/MS method was simple and sensitive. It was found that caffeine naturally existed in Ginkgo biloba leaves,and the contents of caffeine in Ginkgo biloba leaves from different origins varied greatly. This might be related to the climate and origin of the growth. During the extraction processing of Ginkgo biloba,thirty-five percent of caffeine in the raw material would be transferred to the extracts.