Abstract: Black tea is the most important in the world tea production, and is very popular in the world tea market. China has abundant tea resources, especially unused tea leaves in summer and autumn, and there are a few new ways to develop them, such as processing black tea or deep processed products. Application of exogenous enzymes with good functional characteristics, can improve the quality of summer and autumn black teas, and their deep processed products. This article reviews that, the current status and existing problems of exogenous enzymes application in black tea processing in recent years, as well as the types and acting mechanisms of frequently-used exogenous enzymes, transformation of tea components catalyzed by exogenous enzymes during withering, rolling, and fermentation in black tea processing. Utilizing exogenous enzymes to promote the synthesis of theaflavins, a unique component of black tea, and the quality changes in deep-processing of black tea, are also summarized. Exploring the enzymatic processing methods, could promote the efficient utilization of tea resources, and regulate quality of summer and autumn black tea, as well as their deep-processed products, in the future.