In Chinese, 十萬八千里; 十万八千里; shí wàn bā qiān lǐ, 108,000 li, means a great distance. Does anyone knows why they chose 108,000? Is there a poem or historical reason behind this number?
There doesn't seem to be a definitive answer, but one possibility is that the number 108,000 is derived from the 108 auspicious symbols in Tibetan Buddhism. Each of these symbols is said to bring good fortune and blessings, so together they are thought to be especially auspicious.
Additionally, there are said to be 108 energy lines that run through the human body, and 108 beads on a Buddhist rosary.
It probably came from the storybook "西遊記". Below is conservation between "孫悟空(行者)", 沙僧 and 八戒:
其後便有此一說 - 孫悟空一個跟斗十萬八千里... to indicate his extremely powerful ability to travel between locations separated by very long distance. Today, people say "差了十萬八千里" to mean two things are "too far apart", or "not even come close".