En chinois, the middle earth veut dire 中土, ca veut dire le centre de la chine, du pays, au centre de la terre, ou la terre centrale.
I'm afraid I have to explain in English.
China has been a big and proud country in the East for more than 5000 years. It always thought it was in the middle of the earth geograhically. Besides the middle part of China, other smaller tribes are also under China's rule, but geographically they're not in the middle, but to the west, i.e the tribes among the border. This situation is somewhat like the Ryushu islands and Hawaii and Guam nowdays. 中土 refers to the main/middle part of China.
The story in English is The Journey to the West, diff from its french translation. The West means India, and the story was about the Chinese monk and his students going to India to get the books on Buddhism.
http://fr.wikipedia.org/wiki/Le_Voyage_en_Occident.
Pluiepoco, could you give more explanation on 中土?