Kangxi was interested in mathematics, astronomy and geography. It also supports the introduction of western artillery. Contrary to many people's imagination, the early Qing Dynasty actively introduced western military technology. ) He was probably the most proficient person in western science in China at that time, and there was no one. Kangxi's personal interest in science does not mean that the official attitude is to encourage the spread of science. In the middle and early Qing Dynasty, Kangxi and Yong Zhengdi after him were responsible for closing the door to the west. In all fairness, Manchu people were able to enter the Central Plains in the16th century. In fact, their attitude of learning and accepting western science is an important reason.