Red brick is a sintered building brick made of clay, shale and coal gangue. , which is crushed, kneaded and shaped by manual or mechanical pressing, dried and fired with an oxidizing flame at a temperature of about 900 degrees Celsius. It was invented by ancient Romans. At present, there are red bricks on the roofs and walls of many classical buildings in Europe.

In ancient China, the brick-burning technology was mature before the Warring States Period, but at that time, because of the hierarchical system, red bricks could not be burned, and some processes were needed to turn them into blue bricks after burning them.

It was not until the late Qing Dynasty and the Republic of China that China people had a history of burning red bricks.