Abstract: Contents of caffeine and catechin of 243 green tea samples from Guizhou province are detected, using high performance liquid chromatographic (HPLC). The results show that, the catechin contents range 9.14%~27.28% in green tea of Guizhou province, the average content is 15.71%. The caffeine contents range 1.08%~3.33%, the average content is 2.24%. The catechin quality indexes of samples from 9 regions mainly are 1000~2000, and the highest one (the sample is from Qiannan) is 1975.51. The catechin bitter taste index of samples from 9 regions mainly are 8.00~17.04．According to the results, there is high value for making use of effective components of Guizhou green tea, and developing high quality spring tea is strongly recommended, and relatively the autumn tea is suitable for deep processing or extracting active principles.

Key words: Guizhou green tea, active principle, catechin, caffeine