Emperor Kangxi Michelle Ye (1654- 1722) was a rare feudal emperor who loved science in the history of China. In the late Ming and early Qing dynasties, many foreign missionaries came to China to preach. 1689, Emperor Kangxi specially invited French missionaries Zhang Cheng and Bai Jin to the palace to teach the emperor the knowledge of western mathematics and astronomy, and asked them to translate French geometry and algebra books into Chung ying Cheng. Repeated practice, hand-drawing, and not ashamed to ask questions, he learned a wealth of scientific and cultural knowledge. Later, Emperor Kangxi also followed the rules in the palace, devoted himself to studying geometry, and personally compiled a book on triangle theory. He also personally taught geometry and algebra to palace ministers. Kangxi attached great importance to scientific and technological talents. 1705, Kangxi summoned Mei Wending's Sun Meicheng, Chen Houyao, Ming Jiatu and others in Dezhou as "Fa" 172 1 year, and completed 42 volumes of Li Xiang Exam, 5 volumes of Lv Zhengyi, and 53 volumes of Mathematics Essentials, and made statistics. The Essence of Mathematics is a complete elementary mathematics book, which had a very important influence on the development of mathematics in China at that time. Kangxi himself was included in Deng Zongyun.