In this paper, six characteristics of hollowed-out bronzes were analyzed. The technological development can be divided into four development phases. The initial phase is represented by a box with a hollowed-out dragon design from Rui tomb and the Ding with a hollowed-out snake embossment from Xinjiang; the forming phase is represented by Yun’er Zhan and Xugong Ning handles with hollowed-out dragons; the ripe phase is represented by bronze Jin from Xiasi in Xichuan and Zenghou Yi Zun and Pan; the high-level phase is represented by the Chen Zhang Hu. According to the excavated plots and the dates of these bronzes having hollowed-out dragon or snake designs, it is suggested that this technique spread from the Han State to the Chu State and then to the other areas, which include today's Shanxi, Henan, Hubei, Jiangsu and Hebei provinces.