This paper studies China’s short-video industry in the mobile Internet era in 2021 from four aspects，including overview，key points，problems and trends. With the development of digital economy in 2021，the degree of short-video user activity and engagement continued to improve；business scale continued to expand；Douyin was in the lead among the head platforms，and Matthew effect intensified among the short-video APPs；the content of subdivision types was magnifying and content of selling goods was taking off；the short-video industry regulation entered phase 2.0. Focusing on the inside of the industry，there were two distinct features. The head platforms supported brand enterprises，expanded commodity categories，accelerated the construction of live e-commerce ecosystem. The quality of micro drama improved and its commercialization accelerated in the exploration of monetizing. However，with the fast development of the industry，short video infringement disputes were becoming increasingly white-hot in 2021. Looking forward to 2022，in terms of the head plays，improving self-operated e-commerce and accelerating local service connection will be the common key businesses. The content production empowered by technology will drive the competition into a new stage.