The present invention provides a process for preparing fermented tea, by which fermented tea is prepared over a short period of time, while maintaining the physiological activity thereof, and yield of the extract is improved, and a composition, which has favorable flavor and excellent stability and is useful as a functional food. Specifically, the present invention provides a process for preparing fermented tea comprising the step of fermenting tea leaves in the presence of tea leave stems and a composition containing fermented tea extract and dietary fiber.