Abstract: The withering is the first process of black tea, significantly affected the flavour and quality of tea. With the change of time and environment conditions in the withering process, there is a series of physics and chemistry variation in tea leaves. This paper illustrated the major variation of the physical properties, enzymatic activity, biochemical components and aroma in the withering process of black tea, systematically analyzed the key technical factors that had influence on the black tea from temperature, humidity, light to time. The main technology and advanced equipment in withering process of black tea were introduced in detail. It is concluded that the cells change of leaves in the withering process will become the important direction of basic research in the future, and a variety of detection technology can be carried on to help transform information of sensory quality into scientific quantitative index to evaluate the result of the withering process.