According to research, salt is produced in summer in China, which is mainly boiled in seawater. Location: Fujian coastal areas and other places. During the Shang Dynasty, the scale expanded, and salt was made not only from seawater, but also from lake water. There are not only salt workers, but also "salt people" in charge of salt. During the Warring States period, there was pool water to make salt, and there was well salt to cook salt. About 4000 years ago, it shows that China is the earliest salt-making country in the world.