What is the fundamental reason why the corpse does not rot for thousands of years?

There are two kinds of corpses that do not rot in the first thousand years: mummified corpses and wet corpses. Most of them are mummified bodies, such as the female corpse of Loulan, the Egyptian Pharaoh. These are all caused by special conditions, and the necessary condition is dryness. Because the corpse decay is caused by bacteria, and bacteria can't survive in an absolutely dry environment, the corpse decay stops and mummies are formed.

Xin Zhui, the second wet corpse we found in Mawangdui, is an extremely rare wet corpse. The conditions under which she was formed were not accidental. You can watch related programs and have specific video explanations. The coffin is absolutely sealed, so it was isolated from the air until now.