At present, 5G(5th generation mobile communication technology) has been gradually commercialized, but there is a lack of research on the life cycle of 5G patented technology in China. Based on the patent data from 1996 to 2020, the characteristics of Chinese 5G patent applications are investigated, and the Logistic growth model is used to analyze the life cycle of Chinese 5G patent technology. It is found that the annual application volume of domestic 5G patent technology reached its peak in 2018, and it has entered a period of technological decline both as a whole and in terms of major technology categories. China's 5G patent applicants are mainly enterprises and are mainly distributed in four emerging industries: new generation information technology, high-end equipment manufacturing, new materials and digital creativity. Most of the 5G patents in China are applied independently, the proportion of cooperative applications is less than 5%, and the cooperative research and development between enterprises and universities and other institutions is insufficient.