1. After the mid-Tang Dynasty, the agricultural economy in the north was seriously damaged and gradually declined, and the basic economic zone in the Yellow River Basin lost its position as the economic center of gravity.

2. The commercial cities in the Yangtze River valley in Tang Dynasty were centered on Yangzhou and Yizhou (Chengdu). After the Anshi Rebellion, the economic status of the north declined and the status of the Yangtze River Basin rose. Yangzhou and Chengdu have become the most prosperous industrial and commercial cities in China, surpassing Chang 'an and Luoyang in economic status.

3. After the mid-Tang Dynasty, the population migrating south gradually increased. A large number of people from the north moved to the south, which supplemented a large number of labor and advanced production tools and experience in the Central Plains.

The hilly and mountainous areas in the south are also vigorously reclaimed. The expansion of cultivated land area and the improvement of production technology have promoted the increase of grain output.

Second, the performance:

A large number of lakes and fields have been opened up, and the combination of north and south planting techniques has promoted the development of agriculture; Textile technology has made rapid progress, and brocade industry has developed in the middle and lower reaches of the Yangtze River. Metallurgical industry has also developed; The level of porcelain industry is relatively high, the commodity economy has developed initially, and the city has begun to prosper.

Third, the impact:

The development of Jiangnan laid the foundation for China's economic center to move southward. It has a far-reaching impact on China's economy.

Extended data:

Tracing the history of Jiangnan area;

Jiangnan area is a geographical concept with a long history. There are records about Jiangnan in Historical Records and Biography of Five Emperors, and the history of Jiangnan can be traced back to the period of Shun Di. In the process of historical evolution, the concept of "Jiangnan area" is constantly changing. Jiangnan is not only a natural geographical area, but also a socio-economic area, which is a flexible regional concept.

Literally, the "Jiang" here is the Yangtze River, and the so-called "Jiangnan" refers to the area south of the Yangtze River.