Almost every traditional Chinese festival has a connection with legends. The most well-known stories of the Mid Autumn Festival is Chang'e flying to the moon, Jade Rabbit making heavenly medicine, and Wu Gang chopping the cherry bay. Those stories have been passed down from generations to generations alongside the celebrations of the festival itself. Today for young children, listening to the stories is still an important part of their way to celebrate the Festival moon cakes.
Chang'e Flying to the Moon
It is said that long ago there used to be 10 suns in the sky. Each day, one of the suns would travel around the sky on a carriage driven by Xihe, the mother of the suns. One day, unexpectedly, all 10 suns simultaneously appeared in the sky, which instantly dried the crops and caused disaster to the people on earth.
Hou Yi, a local archer, had great sympathy for people's sufferings from the blistering weather and decided to help them out. Houyi climbed up to the summit of Kunlun Mountains and shot down the suns leaving only one to benefit people. After he shot down the sun, Hou Yi became a hero who was revered by local people.
Later, Hou Yi married a beautiful girl—Chang'e. The young couple lived a happy and sweet life.
Hou Yi was so famous for his perfect archery skills that he had a lot of apprentices, including the unrighteous Peng Meng. One day when Hou Yi was on the way to visit his friend, the Queen Mother of the West gave him an elixir of immortality as a reward for his heroic undertaking. Meanwhile, he warned Hou Yi "Do not swallow this pill before preparing yourself with prayer and fasting for a year". Hou Yi gave the elixir to Chang'e for safekeeping and she took it as a treasure and hid it in her jewelry box. Unfortunately, Peng Meng found this secret and made a plan to steal it. Several days later, when Hou Yi and other apprentices went out for hunting, Peng pretended to fall ill and stayed at home. After they left, Peng forced Chang'e to give him the elixir. Chang'e, knowing that she could not defeat Peng, swallowed the elixir herself, and mmediately she felt herself floating up and flied to the sky. With deep love to her husband, Chang'e chose to be an immortal on the moon, closest to the earth; then she could see her husband every day.
In late afternoon, Hou Yi came back and was told what had happened. Heart-stricken, Hou Yi went to the back garden and called his wife's name ceaselessly. Surprisingly, he found that the moon was extremely clean and bright that night; and that there was a moving figure like Chang'e in the moon. Hou Yi desperately tried to catch up with the moon, but he could not do it. Hou Yi then asked servants to set a table in his back garden and with his wife's favorite snacks and fruits on it. In a short time, more and more people heard about the news that Chang'e had become an immortal, and they also put tables under the moon to pray to Chang'e for good fortune and safety. From then on, the custom of worshipping the moon on the Mid-Autumn Festival began to spread in China with Mooncake as its special food.
Source : http://www.chinatravel.com/facts/chinese-festivals/traditional-chinese-festival/Middle-Autumn-Festival.htm#1