In which period did China have the largest plate?

Meta-Empire

Although the Meta-Empire in China's history is only the Central Plains. Kublai Khan is the emperor.

but at that time, the Mongolian empire was too big. So Genghis Khan divided it into six small countries. Divide and rule by your own children. One of these six small countries, the Great Khan, was elected by the Mongolian Golden Family. It is above the "great Khan" of the other five small countries. He is the real "emperor" of the whole Mongolian empire. And Kublai Khan is the "Great Khan". "(although he became the great Khan by means. Not all of them were loyally elected. But he will become one. )

In its heyday, the Mongolian Empire covered an area of 28.4 million-31.8 million square kilometers

But in the traditional history of China, it was thought that the Qing Dynasty was the largest. In the heyday of Qing Dynasty, it was 14 million square kilometers.