What is the boundary between China's east and west parts?

Hu Huanyong line.

This line runs from Aihui, Heilongjiang Province (renamed Aihui in 1956, and Heihe City in 1983) to Tengchong, Yunnan Province, and is roughly a straight line inclined at 45 degrees.

To the southeast of the line, plains, water networks, hills, karst and Danxia landforms are the main geographical structures, while to the northwest is a world of grasslands, deserts and snow-covered plateaus.

The vast majority of the southeastern provinces, autonomous regions and municipalities along this line have urbanization levels higher than the national average; while the vast majority of the northwest provinces and autonomous regions along this line have lower urbanization levels than the national average.

The "Hu Huanyong Line" has also become a dividing line for urbanization levels to some extent.

Reasons for the formation of expanded information: 1. It basically coincides with the 400 mm precipitation line in my country. The geography and climate on both sides are very different, so it is not only the geographical dividing line of my country's population and ethnicity, but also the natural geographical dividing line of my country.

2. It is a historical and geographical dividing line.

Historically, this line was the boundary line between the Central Plains dynasty’s direct influence and centrally controlled territory, the lifeline of war and peace between the Han nation and other ethnic groups, and the dividing line in Chinese history and geography.

3. It is also a dividing line between civilizations: its east is traditional China as understood by most people; while its west is non-Confucian China with diverse beliefs and lifestyles.