The patent is closely related to the technological innovation, and the output of patents is a key indicator for evaluating the technological innovation capability. In some countries, the output of patents has been used to evaluate the technological innovation capability of a country, region or organization. The attractiveness of a technology as an investment object depends decisively on its current life cycle stage. It is a widespread approach to study technology life cycles by observing the evolution of patent applications and the patent maintenance time. Patent activity is also used to describe life cycles at the levels of products and industries from the patent maintenance perspective. The maintenance time of patents also is one of the key indicators for evaluating technological innovation capabilities of their owners. In recent years, the number of patent applications and the number of granted patents in China have both greatly increased. The maintenance time of granted patents in China, especially them of granted patents owned by patentee, gradually became of longer duration. Therefore, the study of the maintenance time of granted patents in China has important significance for the promotion of innovation and industrial development. Five chapters of this book were mainly developed by Yongzhong Qiao, other ten chapters were developed by Yongzhong Qiao and his co-authors. These authors include Xuezhong Zhu, Qi Liang, Siwen Liu, Tiantian Zhang, Yan Sun, Yan Zhang, Wanlin Tan, Jun Shen, and Peng Hao. Their contributions to the book were marked in the right places.