What are the important scientific and technological achievements in ancient China?

The important scientific and technological achievements in ancient China are: lunar calendar, papermaking and compass.

1, lunar calendar.

The ancient calendar of China adopted the combination of Yin and Yang, that is, the cycle of the sun was taken as the year, the cycle of the moon as the month, and the leap month was used to coordinate the relationship between the year and the month. According to the position change of the sun in a year and the evolution order of the ground climate caused by it, the ancients divided the year into 24 segments and 12 months to reflect the four seasons, temperature and phenology.

2. papermaking.

Papermaking was invented in Han Dynasty and Western Han Dynasty and improved in Han Dynasty. Papermaking, especially improved by Cai Lun in the Eastern Han Dynasty (also known as "Cai Hou Paper"), is a revolution in writing materials. It is easy to carry and has a wide range of materials, which has promoted the cultural development of China, Arabia, Europe and even the whole world.

3. compass.

Compass is the result of China ancient working people's understanding of magnet magnetism in long-term practice. As one of four great inventions of ancient china, its invention has played an inestimable role in the development of human science, technology and civilization. In ancient China, the compass was first used for rituals, etiquette, military affairs and divination, and to determine the orientation when looking at geomantic omen.

Geographical achievements:

Northern and Southern Dynasties: ① During the Western Jin Dynasty, Pei Xiu was an outstanding cartographer in ancient China. Draw a map of Gong Yu area, and put forward the principles of drawing a map. (2) The Notes on Water Classics by Li Daoyuan, a geographer in the Northern Wei Dynasty, comprehensively and systematically introduced the physical geography, economic geography and other aspects of the area where the waterway flowed through by annotating the ancient book Water Classics.

Ming and Qing Dynasties: The observation and description of limestone karst landform in Xu Xiake's travel notes in Ming Dynasty was about two centuries earlier than that in Europe. It also recorded some geographical discoveries and corrected some mistakes in previous geographical works.