At that time, Guangzhou was the only trading port allowed by the Qing government. Because of the popularity of Tongcao paintings, Yahang at that time hired thousands of people to specialize in Tongcao paintings. Most Tongcao paintings were used by Western painters to record and understand the daily lives and customs of Chinese people. Because merchants at that time saw business opportunities, they then produced large quantities of Tongcao paintings and sold them to Western countries through treaty ports.

Tongcao paper is cut from a plant called Tongtuomu. For people at that time, this kind of paper was cheap, and if paint was painted on it, it would not be too expensive. It fades with time, so it was loved by many people at the time. Tongcao painting, on the other hand, uses watercolor to draw figures on the paper. After air-drying, the characters on the Tongcao paper are vivid, lifelike and have a strong sense of three-dimensionality. They were very popular among Westerners at the time.

In addition, because cameras had not yet appeared at that time, for Westerners at that time, if they wanted to understand China's history and humanistic customs, they could only show the humanistic features of that time through paintings. It was not until the popularization of photography technology that Westerners gradually lost interest in Tongcao painting. Then Tongcao painting gradually declined and finally declined.

However, a hundred years later, a foreigner brought Tongcao paintings back to Guangzhou, China, and donated all the more than 70 Tongcao paintings in his collection to the Guangzhou Museum, which greatly improved the The research progress of Tongcao painting in China. Although the art of making Tongcao paper has been lost, the skill of Tongcao painting still exists.

The emergence of Tongcao paintings enables Westerners who originally knew little about China to understand Chinese culture and people's local customs from Tongcao paintings. The Tongcao painting is also like a postcard. Although it is a small one, it perfectly presents the people's lives and customs at that time.

This has an important role in promoting the study of ancient history in China, and at the same time, it also allows the Chinese to understand the lives of ancient people.