There are two legends which claim to explain the tradition of eating mooncakes. One Tang Dynasty myth holds that the Earth once had 10 suns circling it. One day all 10 suns appeared at once, scorching the planet with their heat. It was thanks to a skillful archer named Hou Yi that the Earth was saved. He shot down all but one of the suns. As his reward, the Heavenly Queen Mother gave Hou Yi the Elixir of Immortality, but she warned him that he must use it wisely. Hou Yi ignored her advice and, corrupted by fame and fortune, became a tyrannical leader. Chang-Er, his beautiful wife, could no longer stand by and watch him abuse his power so she stole his Elixir and fled to the moon to escape his angry wrath. And thus began the legend of the beautiful woman in the moon, the Moon Fairy.

关于吃月饼这个传统的来历有两个传说。一个是唐朝的神话故事，说的是当时地球被10个太阳包围着。有一天10个太阳同时出现在天空中，巨大的热量几乎把地球烤焦了。多亏一位名叫后羿的神箭手射下了9个太阳，地球才被保住。为了奖励后羿，王母娘娘赐给后羿一种长生不老药，但是王母警告他必须正当使用。然而后羿没有理会王母娘娘的警告，他被名利冲昏了头脑，变成了一个暴君。后羿美丽的妻子嫦娥对他的暴行再也不能袖手旁观，于是她偷走了后羿的长生不老药，飞到月亮上逃避后羿的狂怒。从此就有了关于月宫仙子嫦娥，这个月亮上的美丽女人的传说。 

The second legend has it that during the Yuan Dynasty, an underground group led by Zhu Yuan Zang was determined to rid the country of Mongolian dominance. The moon cake was created to carry a secret message. When the cake was opened and the message read, an uprising was unleashed which successfully routed the Mongolians. It happened at the time of the full moon, which, some say, explains why mooncakes are eaten at this time.
第二个传说讲的是在元朝，朱元璋领导的起义军计划起义来摆脱蒙古族的统治。他们用月饼来传递密信。掰开月饼就可以找到里面的密信，起义军通过这种方式成功的发动了起义，赶走了元朝的统治者。这场起义发生在八月十五之时，于是中秋节吃月饼的习俗便在民间传开来。